Is it safe to climb Carnedd Llewelyn today and tomorrow?

Today on Carnedd Llewelyn is rated Marginal and tomorrow Marginal, from the summit forecast. Summit forecast updated 19:10, 18 Oct. The reasons are below, followed by what the rating can't tell you.

Is it safe to climb Carnedd Llewelyn today?

Marginal Today Sunday 18 October

• Wind and gusts: Summit wind up to 25 mph, gusting 32 mph. That is past the Marginal line (wind 25 mph or gusts 45 mph): expect to be pushed about on ridges and the summit.
• Rain: 21% chance of rain, about 0 mm in all.
• Cloud: Cloud cover averages 41% and humidity 85% at summit height. The forecast gives no cloud base height; the main peak page estimates one from the valley forecast.
• Temperature and wind chill: Up to 4°C at the summit, down to -1°C, feeling as cold as -5°C in the wind. Below freezing at the summit, so expect ice on rock and paths, especially early.
• Daylight: Sunrise 07:48, sunset 18:14: 10h 26m of daylight. The longest route listed here takes about 6h 20m there and back by Naismith's rule, before stops.

Is it safe to climb Carnedd Llewelyn tomorrow?

Marginal Tomorrow Monday 19 October

• Wind and gusts: Summit wind up to 37 mph, gusting 47 mph. That is past the Marginal line (wind 25 mph or gusts 45 mph): expect to be pushed about on ridges and the summit.
• Rain: 73% chance of rain, about 2.6 mm in all. A 60% chance or more makes the day Marginal on its own: wet rock is slippery and wet kit chills you faster.
• Cloud: Cloud cover averages 64% and humidity 93% at summit height. The forecast gives no cloud base height; the main peak page estimates one from the valley forecast.
• Temperature and wind chill: Up to 5°C at the summit, down to 2°C, feeling as cold as -4°C in the wind.
• Daylight: Sunrise 07:49, sunset 18:11: 10h 22m of daylight. The longest route listed here takes about 6h 20m there and back by Naismith's rule, before stops.

What the verdict covers, and what it doesn't

Peakify rates each day Good, Marginal or Poor from the forecast summit wind, gusts, chance of rain and wind chill. Wind of 40 mph or gusts of 65 mph make it Poor; wind of 25 mph, gusts of 45 mph, a 60% chance of rain or a feels-like temperature of -8°C or below make it Marginal. That is all it measures: the weather forecast at the summit.

It does not know your fitness or experience, whether you can navigate in cloud with a map and compass, or what you are carrying. It does not see the state of the path, river levels, snow and ice already on the ground, or how the forecast is changing during the day. A Good day can still go wrong if you start late, turn an ankle or lose the path in mist, and a Marginal day can be fine for an experienced party on the easiest route.

On any day, carry waterproofs, warm layers, a hat and gloves, food, water, a head torch and a charged phone, and know how you would navigate if the top is in cloud. Tell someone your route and when you expect to be down. In winter conditions you need an ice axe and crampons and the skill to use them, or a guide.

Route notes for Carnedd Llewelyn

Ogwen via Carnedd Dafydd

From Glan Dena, Ogwen valley. Up Pen yr Ole Wen and along the ridge over Carnedd Dafydd to Carnedd Llewelyn. Graded Moderate: a hill path, rough or rocky in places, below the Hard and Scramble grades. In cloud, take care to stay on the path. About 4h 30m there and back by Naismith's rule (7.4 km one way, 910 m of ascent).

South-west ridge from Ogwen and Carneddau ridge

From Ogwen Cottage north-side path. A hard mountain walk to the summit from Ogwen Cottage north-side path. Graded Hard: steeper, rougher or longer than the moderate routes, with more time on high, exposed ground. About 4h 10m there and back by Naismith's rule (6.5 km one way, 940 m of ascent).

Gerlan via Yr Elen north-west ridge

From Gerlan public footpath. A hard mountain walk to the summit from Gerlan public footpath. Graded Hard: steeper, rougher or longer than the moderate routes, with more time on high, exposed ground. About 4h 10m there and back by Naismith's rule (6.7 km one way, 890 m of ascent).

Cwm Eigiau via the eastern Foel Grach ridge

From Pen y Gaer hillfort car park. A hard mountain walk to the summit from Pen y Gaer hillfort car park. Graded Hard: steeper, rougher or longer than the moderate routes, with more time on high, exposed ground. About 6h 10m there and back by Naismith's rule (12.0 km one way, 830 m of ascent).

Rachub via Drosgl and Yr Aryg flanks, via Bera Bach

From Rachub upland path junction. A hard mountain walk to the summit from Rachub upland path junction. Graded Hard: steeper, rougher or longer than the moderate routes, with more time on high, exposed ground. About 5h 20m there and back by Naismith's rule (9.8 km one way, 830 m of ascent).

Bwlch y Ddeufaen via Drum and northern ridge

From Bwlch y Ddeufaen mapped track junction. A hard mountain walk to the summit from Bwlch y Ddeufaen mapped track junction. Graded Hard: steeper, rougher or longer than the moderate routes, with more time on high, exposed ground. About 5h 50m there and back by Naismith's rule (11.1 km one way, 840 m of ascent).

Llanfairfechan via Drum and northern ridge

From Llanfairfechan mapped track junction. A hard mountain walk to the summit from Llanfairfechan mapped track junction. Graded Hard: steeper, rougher or longer than the moderate routes, with more time on high, exposed ground. About 6h 20m there and back by Naismith's rule (11.7 km one way, 1,000 m of ascent).

Abergwyngregyn via Drum via Drum and northern ridge

From Abergwyngregyn via Drum mapped track junction. A hard mountain walk to the summit from Abergwyngregyn via Drum mapped track junction. Graded Hard: steeper, rougher or longer than the moderate routes, with more time on high, exposed ground. About 6h 5m there and back by Naismith's rule (11.3 km one way, 960 m of ascent).

Ogwen via Pen yr Helgi Du

From Glan Dena, Ogwen valley. A path over Pen yr Helgi Du, down into Bwlch Eryl Farchog and up the rocky ridge to the summit. Graded Scramble: hands-on rock. Wind and wet rock make a scramble far more serious than its grade, so it is the first route to drop on a Marginal or Poor day. About 4h 45m there and back by Naismith's rule (8.3 km one way, 879 m of ascent).

East Ridge via Ffynnon Lloer and Carneddau ridge

From Glan Denau path junction. A grade 1 scramble to the summit from Glan Denau path junction. Graded Scramble: hands-on rock. Wind and wet rock make a scramble far more serious than its grade, so it is the first route to drop on a Marginal or Poor day. About 4h 30m there and back by Naismith's rule (7.4 km one way, 920 m of ascent).

Crib Lem / Llech Ddu Spur and Carnedd Dafydd

From Gerlan public footpath. A grade 1 scramble to the summit from Gerlan public footpath. Graded Scramble: hands-on rock. Wind and wet rock make a scramble far more serious than its grade, so it is the first route to drop on a Marginal or Poor day. About 5h 20m there and back by Naismith's rule (9.2 km one way, 1,000 m of ascent).

Cwm Llugwy and Craig yr Ysfa

From Cwm Llugwy reservoir access track. A grade 1 scramble to the summit from Cwm Llugwy reservoir access track. Graded Scramble: hands-on rock. Wind and wet rock make a scramble far more serious than its grade, so it is the first route to drop on a Marginal or Poor day. About 3h 20m there and back by Naismith's rule (5.0 km one way, 780 m of ascent).

Cwm Eigiau via Bwlch Eryl Farchog and Craig yr Ysfa

From Cwm Eigiau road-end track. A grade 1 scramble to the summit from Cwm Eigiau road-end track. Graded Scramble: hands-on rock. Wind and wet rock make a scramble far more serious than its grade, so it is the first route to drop on a Marginal or Poor day. About 5h 25m there and back by Naismith's rule (9.7 km one way, 930 m of ascent).

Full distances, ascent and times are on the Carnedd Llewelyn routes page.

In an emergency

Call 999, ask for the police and then mountain rescue. Mountain rescue teams in the UK are volunteers called out through the police. Give your location (a grid reference from a map or phone app if you can), what has happened, how many are in your group and your phone number, then keep the phone free. If you have no signal, try to move to higher ground or text 999; you need to have registered your phone with the emergencySMS service before for a text to work.

Questions about Carnedd Llewelyn

Is it safe to climb Carnedd Llewelyn today?

Today, Sunday 18 October: overcast, up to 4°C at the summit, feeling as cold as -5°C, summit wind 25 mph gusting 32 mph, 21% chance of rain. Rated Marginal. The rating covers the summit weather only; your route, kit and experience matter as much.

Is it safe to climb Carnedd Llewelyn tomorrow?

Tomorrow, Monday 19 October: moderate drizzle, up to 5°C at the summit, feeling as cold as -4°C, summit wind 37 mph gusting 47 mph, 73% chance of rain. Rated Marginal.

How does Peakify decide whether Carnedd Llewelyn is safe to climb?

Peakify rates each day Good, Marginal or Poor from the forecast summit wind, gusts, chance of rain and wind chill. Wind of 40 mph or gusts of 65 mph make it Poor; wind of 25 mph, gusts of 45 mph, a 60% chance of rain or a feels-like temperature of -8°C or below make it Marginal. It does not judge your fitness, kit, navigation or the state of the path.

Who do I call in an emergency on Carnedd Llewelyn?

Call 999, ask for the police and then mountain rescue. Give your location (a grid reference if you can), what happened and how many are in your group. Stay with the casualty and keep them warm.