Climbing Forecast › Snowdonia — Carneddau › Llech Ddu (Black Slab)

SNOWDONIA — CARNEDDAU · RHYOLITE

Llech Ddu (Black Slab) climbing conditions

Poor — wet, too windy or closed

Right now

Temp6°C
Wind43 km/h
Gusts56 km/h
Humidity100%
Rain 48hdry
Last rainNone recent

Assessment

0.3mm rain forecast
Wind 52 km/h, gusts 64 km/h — too windy
Humidity 99% — likely fog/cloud
High humidity (100%) — rhyolite friction compromised, particularly for bouldering

7-day forecast

Scroll through each day — hourly detail is shown inline.

Today Thursday 17 September
Poor
Temp5°C
Rain0.3mm
Wind52 km/h
Gusts64 km/h
Humidity99%
0.3mm rain forecastWind 52 km/h, gusts 64 km/h — too windyHumidity 99% — likely fog/cloud
  • Damp mountain air — upper pitches may stay greasy
  • Very windy — consider sheltered alternatives
Time °C Rain Wind (km/h) Gust Hum
09:00 6° dry 43 56 100%
12:00 6° dry 50 59 99.61%
15:00 5° 0.1mm 54 64 98.19%
18:00 6° 0.2mm 54 65 98.23%
21:00 5° dry 53 66 96.88%
Fri Friday 18 September
Poor
Temp6°C
Rain10mm
Wind69 km/h
Gusts94 km/h
Humidity98%
9.7mm rain forecastWind 69 km/h, gusts 94 km/h — too windyHumidity 98% — likely fog/cloud
  • Wet rhyolite is slippery; seepage from grass above can linger
  • Very windy — consider sheltered alternatives
Time °C Rain Wind (km/h) Gust Hum
06:00 5° dry 40 50 99.06%
09:00 5° dry 46 59 97.95%
12:00 6° 0.1mm 64 82 96.86%
15:00 6° 6mm 75 94 98.87%
18:00 8° 3mm 69 89 99.46%
21:00 9° 0.3mm 63 83 99.4%
Sat Saturday 19 September
Poor
Temp9°C
Rain4mm
Wind44 km/h
Gusts70 km/h
Humidity91%
4.2mm rain forecastWind 44 km/h, gusts 70 km/h — too windyHumidity 91% — potential fog
  • Good temperature for mountain rhyolite
  • Wet rhyolite is slippery; seepage from grass above can linger
  • Very windy — consider sheltered alternatives
Time °C Rain Wind (km/h) Gust Hum
06:00 9° 0.4mm 61 82 99.18%
09:00 9° 1mm 57 78 98.13%
12:00 9° 1mm 48 70 91.52%
15:00 9° 0.6mm 41 63 90.1%
18:00 8° dry 41 59 93.55%
21:00 7° dry 38 53 94.19%
Sun Sunday 20 September
Poor
Temp7°C
Rain0.8mm
Wind28 km/h
Gusts45 km/h
Humidity78%
0.8mm rain forecastWindy — 28 km/h, gusts 45 km/h
  • Wet rhyolite is slippery; seepage from grass above can linger
  • Breezy — helps drying
Time °C Rain Wind (km/h) Gust Hum
06:00 4° dry 32 44 94.68%
09:00 5° dry 29 45 86.4%
12:00 6° dry 27 43 77.33%
15:00 7° dry 29 45 79.56%
18:00 7° 0.2mm 30 41 92.68%
21:00 6° 0.6mm 34 46 97.22%
Mon Monday 21 September
Poor
Temp10°C
Rain2mm
Wind27 km/h
Gusts41 km/h
Humidity97%
2mm rain forecastWindy — 27 km/h, gusts 41 km/hHumidity 97% — likely fog/cloud
  • Good temperature for mountain rhyolite
  • Wet rhyolite is slippery; seepage from grass above can linger
  • Breezy — helps drying
Time °C Rain Wind (km/h) Gust Hum
06:00 8° dry 30 41 99.06%
09:00 9° 0.3mm 29 41 98.46%
12:00 10° 0.2mm 27 41 96.92%
15:00 11° 0.2mm 26 40 96.77%
18:00 10° 0.2mm 26 37 98.57%
21:00 10° 0.1mm 26 35 99.1%
Tue Tuesday 22 September
Poor
Temp10°C
Rain3mm
Wind28 km/h
Gusts45 km/h
Humidity91%
3mm rain forecastWindy — 28 km/h, gusts 45 km/hHumidity 91% — potential fog
  • Good temperature for mountain rhyolite
  • Wet rhyolite is slippery; seepage from grass above can linger
  • Breezy — helps drying
Time °C Rain Wind (km/h) Gust Hum
06:00 8° 0.3mm 32 42 98.1%
09:00 9° 0.3mm 33 46 95.75%
12:00 10° 0.3mm 30 45 91.52%
15:00 10° 0.6mm 26 40 91.05%
18:00 9° 0.6mm 25 33 95.02%
21:00 8° 0.4mm 26 33 95.3%
Wed Wednesday 23 September
Poor
Temp7°C
Rain0.3mm
Wind20 km/h
Gusts36 km/h
Humidity75%
0.3mm rain forecast
Time °C Rain Wind (km/h) Gust Hum
06:00 5° dry 27 34 95.85%
09:00 5° dry 24 36 87.09%
12:00 7° dry 21 36 75.86%
15:00 7° dry 19 32 74.55%
18:00 6° dry 22 29 86.47%
21:00 5° dry 28 33 93.11%
Thu Thursday 24 September
Poor
Temp5°C
Raindry
Wind42 km/h
Gusts—
Humidity—
Should be dryHigh seepage — may still be weepingWind 42 km/h, gusts null km/h — too windy
  • Very windy — consider sheltered alternatives
Time °C Rain Wind (km/h) Gust Hum
06:00 4° dry 38 48 93.64%
09:00 6° dry 42 56 88.23%

About Llech Ddu (Black Slab)

A magnificent crag of great character with complex rock architecture at the head of Cwm Llafar in the Carneddau, sitting between (and distinct from) Ysgolion Duon (the Black Ladders). Multi-pitch trad routes up to 140m; the structure is difficult to comprehend at first acquaintance and old in-situ pegs are typically rusted to crumbly rubbish. Hour-and-a-half approach up Cwm Llafar from Bethesda.

Region
Snowdonia — Carneddau
Rock type
Rhyolite
Aspect
north-facing
Altitude
600m
Exposure
high
Seepage
high

Other crags in this region

Craig yr YsfaYsgolion Duon (Black Ladders)