Compare all 15 summits over 3,000 feet in Eryri before committing to this long and serious mountain challenge.
Every summit is shown side by side. The combined grade gives extra weight to the weakest forecast.
A poor day on the tops of Snowdon - Yr Wyddfa, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Crib y Ddysgl, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Crib Goch, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Elidir Fawr, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Y Garn, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Glyder Fawr, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Glyder Fach, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Tryfan, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Pen yr Ole Wen, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Carnedd Dafydd, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Carnedd Llewelyn, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Yr Elen, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Foel Grach, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Garnedd Uchaf, with drizzle for much of the day and cloud coming and going on the summit.
A poor day on the tops of Foel-fras, with drizzle for much of the day and cloud coming and going on the summit.
Weather data: Open-Meteo (CC BY 4.0). Adapted by Mountain Weather.
Area reference: Glyder Fawr. Local mountain horizons will vary.
Waxing gibbous moon
Moon up during darker hours18:45 BST to 00:30 BST next morning
Window: 19 Oct, 17:00 BST to 20 Oct, 08:00 BST
Area reference: Glyder Fawr. Local mountain horizons will vary.
Waxing gibbous moon
Moon up during darker hours18:45 BST to 01:45 BST next morning
Window: 20 Oct, 17:00 BST to 21 Oct, 08:00 BST
Approximate times in UK local time, for an open horizon. Moon-up periods are rounded to five minutes. Hills and cloud can hide the Moon. Illumination is the sunlit percentage of its disc, not how bright your route will be. Darker hours here begin after civil twilight. This almanac covers only the stated overnight window and does not change the weather grade. Take a headtorch and spare power regardless.
The Welsh 3000s crosses the Yr Wyddfa, Glyderau and Carneddau ranges, taking in 15 summits above 3,000 feet. Its length, exposed scrambling and repeated high ground make a single valley forecast inadequate for choosing a day.
The combined grade is deliberately conservative and gives extra weight to the weakest summit. Review every row, especially Crib Goch and Tryfan, and use the full peak pages for timing and hazard detail.
Read BMC Welsh 3000s guide