Climbing Forecast › North Wales — Llanberis Pass › Cyrn Las

NORTH WALES — LLANBERIS PASS · RHYOLITE

Cyrn Las weather & climbing conditions

Caution — drying out or marginal

Right now

Temp6°C
Wind19 km/h
Gusts22 km/h
Humidity90.82%
Rain 48hdry
Last rainNone recent

Assessment

No recent rain
Humidity 91% — potential fog
High humidity (90.82%) — rhyolite friction compromised, particularly for bouldering
Humidity 90.82% — potential fog/cloud, rock may be damp from condensation

7-day forecast

Scroll through each day — hourly detail is shown inline.

Today Saturday 31 October
Caution
Temp6°C
Raindry
Wind19 km/h
Gusts22 km/h
Humidity91%
No recent rainHumidity 91% — potential fog
  • Damp mountain air — upper pitches may stay greasy
Time °C Rain Wind (km/h) Gust Hum
15:00 6° dry 19 22 90.82%
18:00 6° dry 12 18 89.13%
21:00 6° dry 16 18 88.75%
Sun Sunday 1 November
Poor
Temp4°C
Rain0.7mm
Wind27 km/h
Gusts36 km/h
Humidity98%
0.7mm rain forecastWindy — 27 km/h, gusts 36 km/hHumidity 98% — likely fog/cloud
  • Wet rhyolite is slippery; seepage from grass above can linger
  • Breezy — helps drying
Time °C Rain Wind (km/h) Gust Hum
06:00 5° 0.4mm 29 36 99.97%
09:00 4° 0.3mm 30 40 99.49%
12:00 4° dry 26 36 97.94%
15:00 4° dry 28 36 97.58%
18:00 4° dry 28 35 99.04%
21:00 4° dry 28 36 97.71%
Mon Monday 2 November
Caution
Temp2°C
Raindry
Wind30 km/h
Gusts45 km/h
Humidity86%
Should be dryWindy — 30 km/h, gusts 45 km/hHumidity 86% — potential fog
  • Cold mountain conditions — pack warm belay layers
  • Damp mountain air — upper pitches may stay greasy
  • Breezy — helps drying
Time °C Rain Wind (km/h) Gust Hum
06:00 0° dry 34 43 95.35%
09:00 1° dry 36 46 94.75%
12:00 2° dry 29 42 86.11%
15:00 3° dry 31 45 86.24%
18:00 2° dry 30 43 94.39%
21:00 1° dry 33 47 93.63%
Tue Tuesday 3 November
Caution
Temp3°C
Raindry
Wind33 km/h
Gusts53 km/h
Humidity89%
Should be dryWindy — 33 km/h, gusts 53 km/hHumidity 89% — potential fog
  • Cold mountain conditions — pack warm belay layers
  • Damp mountain air — upper pitches may stay greasy
  • Breezy — helps drying
Time °C Rain Wind (km/h) Gust Hum
06:00 0° dry 35 49 97.27%
09:00 1° dry 36 52 95.08%
12:00 2° dry 33 53 88.75%
15:00 3° dry 33 51 88.97%
18:00 2° dry 37 53 92.63%
21:00 2° dry 40 57 92.69%
Wed Wednesday 4 November
Poor
Temp3°C
Raindry
Wind40 km/h
Gusts62 km/h
Humidity84%
Should be dryWind 40 km/h, gusts 62 km/h — too windy
  • Cold mountain conditions — pack warm belay layers
  • Very windy — consider sheltered alternatives
Time °C Rain Wind (km/h) Gust Hum
06:00 1° dry 41 59 95.19%
09:00 1° dry 43 63 93.11%
12:00 2° dry 40 62 86.36%
15:00 3° dry 40 60 82.61%
18:00 2° dry 45 64 87.56%
21:00 1° dry 49 70 89.85%
Thu Thursday 5 November
Poor
Temp2°C
Raindry
Wind39 km/h
Gusts63 km/h
Humidity84%
Should be dryWind 39 km/h, gusts 63 km/h — too windy
  • Cold mountain conditions — pack warm belay layers
  • Very windy — consider sheltered alternatives
Time °C Rain Wind (km/h) Gust Hum
06:00 0° dry 46 65 94.12%
09:00 1° dry 47 68 91.26%
12:00 2° dry 41 63 84.26%
15:00 2° dry 38 57 84.37%
18:00 2° dry 41 57 90.2%
21:00 1° dry 41 57 91.79%
Fri Friday 6 November
Caution
Temp2°C
Raindry
Wind25 km/h
Gusts42 km/h
Humidity90%
Should be dryWindy — 25 km/h, gusts 42 km/hHumidity 90% — potential fog
  • Cold mountain conditions — pack warm belay layers
  • Damp mountain air — upper pitches may stay greasy
  • Breezy — helps drying
Time °C Rain Wind (km/h) Gust Hum
06:00 0° dry 32 45 95.6%
09:00 1° dry 31 45 93.13%
12:00 1° dry 27 42 89.27%
15:00 2° dry 24 36 90.42%
18:00 1° dry 24 33 94.93%
21:00 1° dry 23 31 96.39%
Sat Saturday 7 November
Caution
Temp2°C
Raindry
Wind18 km/h
Gusts31 km/h
Humidity90%
Should be dryHumidity 90% — potential fog
  • Cold mountain conditions — pack warm belay layers
  • Damp mountain air — upper pitches may stay greasy
Time °C Rain Wind (km/h) Gust Hum
06:00 0° dry 20 27 97.9%
09:00 0° dry 21 29 95.69%
12:00 2° dry 19 31 89.73%
15:00 2° dry 17 27 89.6%

About Cyrn Las

A serious 150m rhyolite mountain crag hidden high in Cwm Glas Mawr on the south side of the Llanberis Pass — remote in feel despite its position above the road. Cold, north-facing, and slow to come into condition, Cyrn Las needs a proper dry spell. Steep 45–60 minute walk-in from the pass. Best kept for a settled forecast after the sunnier Pass crags have already dried.

Region
North Wales — Llanberis Pass
Rock type
Rhyolite
Aspect
north-facing
Altitude
550m
Exposure
high
Seepage
high

Other crags in this region

Carreg WastadClogwyn y GrochanCraig DduCromlech BouldersDinas CromlechDinas Mot