A wild day on the tops of Elidir Fawr, with very strong, gusty winds and sleet or snow up high. Not a day for the summit.
Things to watch
Burns could rise quickly through much of the day and into the evening. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a north-westerly wind of around 20–30 mph first thing, rising to 35–45 mph by midday, with gusts of 45–55 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges.
Cloud and visibility
Cloud on the tops early should lift off them by early afternoon. The cloud base could be as low as 300–600 m early in the morning. In cloud you'll be finding your way without landmarks, so carry navigation you trust and know how to use, with a backup such as a spare battery or a map and compass.
Rain and ground
Sleet is possible on the tops, and it could turn to snow if it is a little colder. Heavy rain early on, turning lighter by early afternoon. Expect 10–20 mm in total, measured as melted water, so any snow would lie deeper. Totals are uncertain and could be higher.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -8 to -4°C in the wind. The freezing level falls through the day, to around 1100–1400 m by midday. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 6:10pm, so allow time to get off the hill before dark, and carry a head torch.
Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 1 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Cloud may obscure this summit even while the surrounding model grid indicates sunshine. The low cloud-free summit estimate is a reason to be cautious about expecting views.
Morning · 08:00–12:00
Severe hill conditionsSummit winds around 15-25 mph early in the morning, strengthening to 30-40 mph later. Gusts around 40-50 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges. Rain is forecast during this period. Rain is forecast during the morning, but models differ considerably on the amount.
-11
Afternoon · 12:00–17:00
Severe hill conditionsWinds strengthen compared with the morning. Summit winds around 30-40 mph. Gusts around 45-55 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.
-13
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaToo windy for an exposed pitch above about 600 m (gusts of about 50 mph). Lower down, a poor night to camp on open ground.19Poor · 600 mView detailsHide details
Night beginning Wednesday 21 October 2026
Full overnight outlook
Too windy for an exposed pitch above about 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 50 mph around 900 m and nearer 35 mph around 300 m, enough to damage a tent on open ground. Pitch low down and in real shelter, or leave it for another night. Dry to pitch, then some light rain overnight and into the morning, so expect to pack a wet tent. Above about 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 21 Oct, 17:00 BST to 22 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39 · poor
Wind / gust
16 mph / 36 mph
Typical / low
5.5°C / 4.9°C · a brief spell
In cloud
0% of modelled night
Condensation
Moderate
600 m19 · very poor
Wind / gust
19 mph / 43 mph
Typical / low
4.7°C / 4.1°C · much of the night
In cloud
33% of modelled night
Condensation
Moderate
900 m9 · very poor
Wind / gust
22 mph / 51 mph
Typical / low
2.5°C / 2.0°C · much of the night
In cloud
33% of modelled night
Condensation
Moderate
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 45–55 mph.Poor0View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 45–55 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust45-55 mphRain15.5 mm
Main factorsgusts of 45–55 mphwet rock likelymuch of the route may be in cloud
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Wednesday 21 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
Summit wind · 08:00-17:0010-20 mph southwesterlySummit gusts · 08:00-17:0020-30 mphFeels like-6 to -2°CPrecipitationUp to around 2 mmCloud-free summit estimate85%Cloud base through day1,100-1,600 mFreezing levelAbove summitDaylightSunrise 07:54 · Sunset 18:05 · 10.2 hours daylight
The day on the hill
A good day on Elidir Fawr: light winds and clear tops for most of the day.
Wind
On the summit expect a south-westerly wind of 10–20 mph for most of the day, with gusts of 20–30 mph at the windiest. Lower down on the open hillside it will be more like 5–15 mph. It gets windier still after dark, with summit gusts of 25–35 mph, so bear that in mind if you will be out late.
Cloud and visibility
The tops are likely to drift in and out of cloud, with the best chance of a clear summit around midday. The cloud base could be as low as 700–1000 m mid-morning. A few forecast models bring it lower still, to around 400–700 m. It will look largely cloudy overhead, but that cloud should mostly stay above the tops. The air should be clear, so expect far-reaching views as long as the tops stay clear.
Rain and ground
Drizzle at first, clearing by mid-morning. More rain follows after dark. Some forecast models keep it drier later on. It will be wet underfoot after recent rain.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -6 to -2°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 6.7 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
GoodSummit winds around 10-20 mph. Gusts around 15-25 mph are possible on exposed ground. Rain is forecast during this period.
76
Afternoon · 12:00–17:00
GoodSummit winds around 10-20 mph. Gusts around 20-30 mph are possible on exposed ground.
80
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaToo windy for an exposed pitch above about 600 m (gusts of about 50 mph and around 17 mm of rain). Lower down, a poor night to camp on open ground.19Poor · 600 mView detailsHide details
Night beginning Thursday 22 October 2026
Full overnight outlook
Too windy for an exposed pitch above about 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 50 mph around 900 m and nearer 35 mph around 300 m, enough to damage a tent on open ground. Pitch low down and in real shelter, or leave it for another night. The wind swings from southerly to southwesterly overnight, so a pitch sheltered at dusk may not be by morning. Expect a wet night, around 17 mm of rain, with rain while you pitch and still falling when you pack up. Above about 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 3°C at 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Cloud at the reference camping height may hide the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 22 Oct, 17:00 BST to 23 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39 · poor
Wind / gust
18 mph / 36 mph
Typical / low
7.4°C / 6.6°C · much of the night
In cloud
0% of modelled night
Condensation
High
600 m19 · very poor
Wind / gust
22 mph / 44 mph
Typical / low
6.3°C / 5.2°C · much of the night
In cloud
47% of modelled night
Condensation
High
900 m9 · very poor
Wind / gust
26 mph / 52 mph
Typical / low
4.3°C / 3.2°C · much of the night
In cloud
53% of modelled night
Condensation
High
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 20–30 mph will be noticeable on exposed ridges. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust20-30 mphRain1.0 mm
Main concernwet rock likely
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Thursday 22 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A wild day on the tops of Elidir Fawr, with very strong, gusty winds and burns likely to be in spate. Not a day for the summit.
Things to watch
Burns and rivers are likely to be in spate through much of the day and into the evening, so unbridged crossings could be difficult or impossible. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a north-westerly wind of 10–55 mph for most of the day, with gusts of 65–75 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges.
Cloud and visibility
Cloud on the tops early should lift off them by early afternoon. The cloud base could be as low as 400–700 m mid-morning. Visibility may drop briefly in showers.
Rain and ground
Sleet is possible on the tops, and it could turn to snow if it is a little colder. Heavy rain early on, turning lighter by early afternoon. Expect 10–20 mm in total, measured as melted water, so any snow would lie deeper. Totals are uncertain and could be higher. It will be wet underfoot after recent rain.
Warmth and kit
On the tops it will be around -2 to 2°C, feeling like -10 to -6°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 6:05pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
There is some disagreement between forecast models on wind strength. It's still two days off and could change, so check again nearer the time.
Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 4.3 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
Severe hill conditionsSummit winds around 20-30 mph early in the morning, strengthening to 45-55 mph later. Gusts around 65-75 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is forecast during the morning, but models differ considerably on the amount.
-39
Afternoon · 12:00–17:00
Severe hill conditionsWinds strengthen compared with the morning. Summit winds around 40-50 mph. Gusts around 60-70 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period. Some forecast models bring rain during the afternoon, while others keep it mostly dry.
-22
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 60 mph and about 4 mm of rain.9Poor · 600 mView detailsHide details
Night beginning Friday 23 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 60 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. The wind swings from northwesterly to southwesterly overnight, so a pitch sheltered at dusk may not be by morning. Expect about 4 mm of rain, with rain while you pitch and still falling when you pack up. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 23 Oct, 17:00 BST to 24 Oct, 08:00 BST. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19 · very poor
Wind / gust
23 mph / 41 mph
Typical / low
5.1°C / 4.9°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
600 m9 · very poor
Wind / gust
28 mph / 49 mph
Typical / low
4.3°C / 4.1°C · much of the night
In cloud
7% of modelled night
Condensation
Moderate
900 m9 · very poor
Wind / gust
33 mph / 58 mph
Typical / low
1.9°C / 1.6°C · much of the night
In cloud
20% of modelled night
Condensation
Moderate
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 65–75 mph.Poor0View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 65–75 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust65-75 mphRain15.4 mm
Main factorsgusts of 65–75 mphwet rock likelymuch of the route may be in cloud
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Friday 23 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A wild day on the tops of Elidir Fawr, with a real risk of thunderstorms and very strong, gusty winds. Not a day for the summit.
Things to watch
There is a real risk of thunderstorms from around midday into the evening. Keep off exposed summits and ridges while storms are around. Storms can bring sudden strong gusts and heavy rain. Storm timing could easily shift by a few hours. Burns and rivers are likely to be in spate through the day and overnight, so unbridged crossings could be difficult or impossible. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a south-westerly wind of around 30–40 mph first thing, rising to 45–55 mph by early afternoon, with gusts of 65–75 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. If the windier forecast models are right, summit gusts could reach 80–90 mph.
Cloud and visibility
Expect the summit to be in cloud for most of the day. The cloud base could be as low as 300–600 m in the early afternoon. In cloud you'll be finding your way without landmarks, so carry navigation you trust and know how to use, with a backup such as a spare battery or a map and compass.
Rain and ground
Rain for much of the day, heaviest in the early afternoon. Expect 20–40 mm in total. Heavier showers can bring sudden strong gusts and a quick drop in visibility. Totals are uncertain and could be higher. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -6 to -2°C in the wind. It turns milder through the day. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 6pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
It's still three days off and could change, so check again nearer the time.
Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 0 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
Severe hill conditionsSummit winds around 30-40 mph early in the morning, strengthening to 40-50 mph later. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Some forecast models bring rain during the morning, while others keep it mostly dry.
-16
Afternoon · 12:00–17:00
Severe hill conditionsWinds strengthen compared with the morning. More rain is expected. Summit winds around 40-55 mph. Gusts around 65-75 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.
-80
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 75 mph and around 11 mm of rain.0Poor · 600 mView detailsHide details
Night beginning Saturday 24 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 75 mph around 900 m and nearer 50 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect a wet night, around 11 mm of rain, with rain while you pitch and still falling when you pack up. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 24 Oct, 17:00 BST to 25 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m9 · very poor
Wind / gust
36 mph / 52 mph
Typical / low
6.2°C / 5.5°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m0 · very poor
Wind / gust
43 mph / 63 mph
Typical / low
4.7°C / 4.2°C · much of the night
In cloud
0% of modelled night
Condensation
Low
900 m0 · very poor
Wind / gust
51 mph / 74 mph
Typical / low
2.4°C / 2.0°C · much of the night
In cloud
0% of modelled night
Condensation
Low
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 65–75 mph are strong enough to make movement extremely difficult on exposed ground. During the strongest gusts, walking or standing may be impossible and you could be blown off your feet. Avoid exposed high ground. Cloud on the tops may make route-finding and retreat harder. There is a real risk of thunderstorms from around midday into the evening. Keep off exposed rock and ridges while storms are around. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust65-75 mphRain29.7 mm
Main factorshigh thunderstorm risk on exposed groundgusts of 65–75 mphwet rock likely
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Saturday 24 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A wild day on the tops of Elidir Fawr, with very strong, gusty winds and rain for much of the day. Not a day for the summit.
Things to watch
Burns could rise quickly through much of the day and into the evening. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a north-westerly wind of 40–55 mph for most of the day, with gusts of 65–75 mph at the windiest. Lower down on the open hillside it will be more like 15–25 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges.
Cloud and visibility
The tops are likely to drift in and out of cloud, with the best chance of a clear summit around midday. The cloud base could be as low as 700–1000 m mid-morning. A few forecast models bring it lower still, to around 400–700 m. Visibility may drop briefly in showers.
Rain and ground
Rain for much of the day. Expect 5–10 mm in total. Some forecast models keep it drier in the morning. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 0 to 4°C, feeling like -8 to -4°C in the wind. The freezing level is close to summit height. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 5pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
There is some disagreement between forecast models on wind strength. It's still four days off and could change, so check again nearer the time.
Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans. Below zero means severe hill conditions. More negative scores indicate more severe forecast weather. Read the hazard details before making plans.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 7.3 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
Severe hill conditionsSummit winds around 45-55 mph. Gusts around 65-75 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Summit cloud becomes more persistent later. Rain is forecast during this period. Rain is possible during the morning, but forecast models disagree on whether it will fall.
-26
Afternoon · 12:00–17:00
PoorSummit winds around 40-50 mph. Gusts around 55-65 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is possible during the afternoon, but forecast models disagree on whether it will fall.
7
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaToo windy for an exposed pitch above about 600 m (gusts of about 55 mph). Lower down, a poor night to camp on open ground.19Poor · 600 mView detailsHide details
Night beginning Sunday 25 October 2026
Full overnight outlook
Too windy for an exposed pitch above about 600 m. Lower down, a poor night to camp on open ground. Gusts reach about 55 mph around 900 m and nearer 40 mph around 300 m, enough to damage a tent on open ground. Pitch low down and in real shelter, or leave it for another night. The wind swings from northwesterly to southwesterly overnight, so a pitch sheltered at dusk may not be by morning. Expect some light rain, with rain while you pitch and still falling when you pack up. A cold night, down to about 2°C around 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 25 Oct, 17:00 GMT to 26 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m39 · poor
Wind / gust
17 mph / 38 mph
Typical / low
5.3°C / 5.2°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m19 · very poor
Wind / gust
20 mph / 46 mph
Typical / low
4.7°C / 4.6°C · much of the night
In cloud
0% of modelled night
Condensation
Low
900 m9 · very poor
Wind / gust
23 mph / 54 mph
Typical / low
2.4°C / 2.1°C · much of the night
In cloud
0% of modelled night
Condensation
Low
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 65–75 mph.Poor0View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 65–75 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust65-75 mphRain8.9 mm
Main factorsgusts of 65–75 mphwet rock likely
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Sunday 25 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A poor day on the tops of Elidir Fawr, with very strong, gusty winds and burns likely to be in spate.
Things to watch
Burns and rivers are likely to be in spate through the day and overnight, so unbridged crossings could be difficult or impossible. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a south-westerly wind of around 20–30 mph first thing, rising to 35–45 mph by mid-afternoon, with gusts of 45–55 mph at the windiest. Lower down on the open hillside it will be more like 10–20 mph. Gusts like that are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. If the windier forecast models are right, summit gusts could reach 60–70 mph.
Cloud and visibility
The tops are likely to drift in and out of cloud, with the best chance of a clear summit early in the morning. The cloud base could be as low as 400–700 m mid-afternoon. In cloud you'll be finding your way without landmarks, so carry navigation you trust and know how to use, with a backup such as a spare battery or a map and compass.
Rain and ground
Rain for much of the day, becoming heavier later. Expect 10–20 mm in total. Totals are uncertain and could be higher. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 2 to 6°C, feeling like -4 to 0°C in the wind. It turns milder through the day. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 4:55pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
It's still five days off and could change, so check again nearer the time.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 0 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
PoorSummit winds around 20-35 mph. Gusts around 40-50 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges. Rain is forecast during this period. Some forecast models bring rain during the morning, while others keep it mostly dry.
26
Afternoon · 12:00–17:00
Severe hill conditionsWinds strengthen compared with the morning. More rain is expected. Summit winds around 30-40 mph. Gusts around 45-55 mph are possible on exposed ground. Gusts this strong can make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Rain is forecast during this period. Rain is forecast during the afternoon, but models differ considerably on the amount.
-12
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 65 mph and heavy rain, around 50 mm.9Poor · 600 mView detailsHide details
Night beginning Monday 26 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 65 mph around 900 m and nearer 45 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Expect heavy rain, around 50 mm, with rain while you pitch and still falling when you pack up. Above about 600 m you'd likely be in cloud for part of the night: damp, and hard to find your way if you need to move. Overnight lows of about 7°C at 900 m. A 3-season bag rated to about 6°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Cloud at the reference camping height may hide the Moon. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 26 Oct, 17:00 GMT to 27 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19 · very poor
Wind / gust
29 mph / 45 mph
Typical / low
12.7°C / 9.3°C · a brief spell
In cloud
0% of modelled night
Condensation
High
600 m9 · very poor
Wind / gust
35 mph / 54 mph
Typical / low
11.6°C / 8.3°C · several hours
In cloud
80% of modelled night
Condensation
High
900 m0 · very poor
Wind / gust
41 mph / 64 mph
Typical / low
10.2°C / 6.6°C · several hours
In cloud
87% of modelled night
Condensation
High
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 6°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 45–55 mph.Poor0View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 45–55 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust45-55 mphRain15.2 mm
Main factorsgusts of 45–55 mphwet rock likelymuch of the route may be in cloud
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Monday 26 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A poor day on the tops of Elidir Fawr, with burns in severe spate and drizzle clearing by midday.
Things to watch
Burns and rivers are likely to be in severe spate from the morning into the evening. Do not attempt unbridged crossings. Timings are rough. Turn back if a crossing looks unsafe.
Wind
On the summit expect a westerly wind of 15–30 mph for most of the day, with gusts of 30–40 mph at the windiest. Lower down on the open hillside it will be more like 5–15 mph. Gusts like that will be noticeable on ridges and open tops, and you will chill quickly when you stop.
Cloud and visibility
The tops should stay clear of cloud all day.
Rain and ground
Drizzle at first, clearing by midday. Expect 2–5 mm in total. Some forecast models keep it drier in the morning. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 2 to 6°C, feeling like -2 to 2°C in the wind. The freezing level is above the summits. Take a hat, gloves, a windproof and a spare warm layer. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 4:55pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
It's still six days off and could change, so check again nearer the time.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 8.8 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
PoorSummit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Rain is forecast during this period. Some forecast models bring rain during the morning, while others keep it mostly dry.
30
Afternoon · 12:00–17:00
PoorRain eases compared with the morning. Summit winds around 15-25 mph. Gusts around 25-35 mph are possible on exposed ground.
30
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaNot a night to camp on the open hill: gusts of about 55 mph and about 4 mm of rain.9Poor · 600 mView detailsHide details
Night beginning Tuesday 27 October 2026
Full overnight outlook
Not a night to camp on the open hill. Gusts reach about 55 mph around 900 m and nearer 40 mph around 300 m, strong enough to flatten or tear a tent. Don't count on finding shelter once you're up there. Choose another night or a low, sheltered spot. Dry to pitch, then about 4 mm of rain overnight and into the morning, so expect to pack a wet tent. Overnight lows of about 5°C at 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 27 Oct, 17:00 GMT to 28 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m19 · very poor
Wind / gust
23 mph / 39 mph
Typical / low
6.6°C / 5.4°C · much of the night
In cloud
0% of modelled night
Condensation
Low
600 m9 · very poor
Wind / gust
28 mph / 47 mph
Typical / low
6.6°C / 5.4°C · much of the night
In cloud
0% of modelled night
Condensation
Low
900 m9 · very poor
Wind / gust
33 mph / 56 mph
Typical / low
5.4°C / 5.0°C · a brief spell
In cloud
20% of modelled night
Condensation
Low
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaMixed conditions for exposed scrambling: gusts of 30–40 mph.Poor45View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Mixed conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 30–40 mph could throw you off balance on exposed moves and ridges. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust30-40 mphRain2.8 mm
Main factorsgusts of 30–40 mphwet rock likely
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Tuesday 27 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.
A poor day on the tops of Elidir Fawr, with strong, gusty winds and rain for much of the day.
Wind
On the summit expect a south-westerly wind of around 30–40 mph first thing, easing to 20–30 mph by mid-afternoon, with gusts of 45–55 mph at the windiest. Lower down on the open hillside it will be more like 5–15 mph. Gusts like that are strong enough to knock you off balance, so take care near edges and on narrow ridges. If the windier forecast models are right, summit gusts could reach 65–75 mph.
Cloud and visibility
Expect the summit to be in cloud for most of the day. The cloud base could be as low as 700–1000 m early in the morning. In cloud you'll be finding your way without landmarks, so carry navigation you trust and know how to use, with a backup such as a spare battery or a map and compass.
Rain and ground
Rain for much of the day. Expect 5–10 mm in total. The ground is very wet after recent rain, so expect boggy paths.
Warmth and kit
On the tops it will be around 6 to 10°C, feeling like 0 to 4°C in the wind. The freezing level is above the summits. A windproof and an extra layer for stops will help. Pack waterproofs too, and keep a warm layer dry in your pack.
Daylight
Sunset is around 4:55pm, so allow time to get off the hill before dark, and carry a head torch.
Forecast confidence
It's still seven days off and could change, so check again nearer the time.
Sunshine context Model-grid estimate, not summit sunshine
The surrounding model grid indicates 0 h of sunshine. This is not a forecast of time in sunshine on the summit. Use the cloud and views outlook above for the conditions on this mountain.
Morning · 08:00–12:00
PoorSummit winds around 30-40 mph. Gusts around 45-55 mph are possible on exposed ground. Gusts this strong can knock you off balance, so take care near edges and on narrow ridges. Rain is forecast during this period.
2
Afternoon · 12:00–17:00
PoorWinds ease compared with the morning. Summit winds around 20-30 mph. Gusts around 30-40 mph are possible on exposed ground. Gusts this strong can make walking into it hard work, with buffeting on ridges and edges. Summit cloud is more persistent early in this period, with better prospects later. Rain is forecast during this period.
31
Compare an early start with later conditions. The main forecast above covers the day in more detail.
Overnight · 17:00–08:00Wild campingBetaA mixed night to camp, mainly because of the wind: gusts of about 30 mph.59Mixed · 600 mView detailsHide details
Night beginning Wednesday 28 October 2026
Full overnight outlook
A mixed night to camp, mainly because of the wind. Gusts reach about 30 mph on open ground, so peg out well and use the guylines. Look for shelter from the west. Expect a little rain, mostly early on, so you'll likely pitch in the rain. Overnight lows of about 4°C at 900 m. A 3-season bag rated to about 2°C comfort, and a warm mat, should do. Allow more if you sleep cold. The ground will be sodden after recent rain, so pick a firm, well-drained pitch.
Extensive cloud may limit moonlight. Illumination describes the sunlit part of the Moon, not brightness at your pitch.
Overnight window: 28 Oct, 17:00 GMT to 29 Oct, 08:00 GMT. Approximate open-horizon times; hills can hide the Moon. Still take a headtorch.
Elevation reference (open ground)
300 m59 · mixed
Wind / gust
11 mph / 21 mph
Typical / low
5.0°C / 4.7°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
600 m59 · mixed
Wind / gust
14 mph / 25 mph
Typical / low
5.0°C / 4.7°C · several hours
In cloud
0% of modelled night
Condensation
Moderate
900 m59 · mixed
Wind / gust
16 mph / 30 mph
Typical / low
4.2°C / 3.7°C · much of the night
In cloud
7% of modelled night
Condensation
Moderate
Warmth planning: As a broad starting point, consider a 3-season bag with an ISO/EN comfort rating at or below about 2°C. Allow more margin if you sleep cold or expect fatigue, and use an adequate insulated mat. Dampness is possible, so keep the sleep system dry and ensure its insulation remains effective if damp.
The ground is likely to be very wet after recent rain. Expect boggy approaches and choose a durable pitch carefully.
Did this match your night?Share a quick observation to help improve this beta forecast.Give feedback →
Daytime · exposed rockClimbing & scramblingBetaVery poor conditions for exposed scrambling: gusts of 45–55 mph.Poor0View detailsHide details
Generic exposed-rock guidance
Full climbing & scrambling outlook
Very poor conditions for exposed scrambling. The rock is likely to be wet and slippery through the day. Gusts of 45–55 mph are strong enough to make walking very difficult and tiring, with a risk of being blown off your feet. Avoid exposed ridges and edges. Cloud on the tops may make route-finding and retreat harder. The rock around the summit is mostly sandstone, a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. On the usual routes up you may also cross mudstone or slate, which has only fair grip even when dry and is slippery when wet. These are general notes for each rock type, taken from geological maps around the summit, so the rock on your line may differ.
Rock surfaceWet rock likelyPeak gust45-55 mphRain6.2 mm
Main factorsgusts of 45–55 mphwet rock likelymuch of the route may be in cloud
Most common mapped rock around the summit
SandstoneAllt Lwyd Formation
Origin
Sedimentary
Broad rock-response group
Sandstone or gritstone
Mapping
BGS Geology 50K · 1:50,000
Summit area
Sandstone or gritstone in 59% of 17 BGS samples within 350 m
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away. These are general notes for each rock type, from geological map samples at and around the summit. The rock on your line can differ, and lichen, vegetation and seepage all change how it feels underfoot.
Rock groups along the sampled routes
These are mapped rock groups, not separate weather forecasts or a ranking of route safety.
Elidir Fawr Ridge
slate or mudstone, volcanic rock, sandstone or gritstone
Geological detail and BGS records
Mapped variation
9 rock types appear in the mapped samples
Samples around the summit inform the main rock-response profile, with the summit pin shown separately where it differs. Route samples add further context, but this is not a continuous geological survey.
Summit-area sample
SandstoneAllt Lwyd FormationAround 515 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Summit-area sample
SiltstoneNant Ffrancon Subgroup107–399 m samplesSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Route sample
Felsic tuffLower Rhyolitic Tuff FormationAround 818 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
Pyroclastic rockBedded Pyroclastic FormationAround 611 mSeen on Peak Elidir Fawr Ridge
Volcanic tuff is rock formed from compacted volcanic ash and debris. It is rough and grippy when dry and usually still grips reasonably when wet. It is mostly solid, in slabs and ledges, though weathered patches can be crumbly.
BGS record →
Route sample
RhyoliteUnnamed Igneous Intrusion, OrdovicianAround 303 mSeen on Peak Elidir Fawr Ridge
Rhyolite is a hard, fine-grained volcanic rock. It grips well when dry and gets slippery on smoother faces when wet. It is hard, but often cracked into sharp, blocky pieces, so some holds are loose.
BGS record →
Route sample
SandstoneCwm Eigiau FormationAround 914 mSeen on Peak Elidir Fawr Ridge
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
BGS record →
Route sample
SiltstoneLower Rhyolitic Tuff FormationAround 203 mSeen on Peak Elidir Fawr Ridge
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
Mudstone, siltstone and sandstoneMarchlyn Formation
Mudstone or slate is a soft, fine-grained rock that splits into thin flakes. It has only fair grip even when dry and is slippery when wet. It is often shattered, breaking into loose flakes, scree and poor holds.
BGS record →
Summit-area sample
GritstoneCarnedd Y Filiast Grit Member
Sandstone is a gritty sedimentary rock. It is rough and grippy when dry and can feel greasy when damp or covered in lichen. It is usually solid in terraced steps, but softer layers crumble and weathered edges can break away.
Recommended kit for this dayWeather-aware packing prompts, plus your core hillwalking kitView kit
For a day hillwalk, not a complete route-specific checklist. Carry navigation and backup you can use, warm and waterproof layers, suitable footwear, food and water, a headtorch, emergency shelter, first aid and a way to call for help. Snow, ice, technical terrain and overnight trips need additional equipment and skills.
Does the weather shape your plans?Optional hill-user research. One answer helps; further questions are up to you.Take part
Help the Mountain Decisions Project understand how forecasts influence hill days, including when plans stay the same. Findings will be shared publicly as summaries, not individual responses.
This is about Elidir Fawr on Wednesday 28 October 2026. It asks about intentions, not whether you actually went out. No name or account is needed.