Afon Las from Nant Peris up Glyder Fawr: route map, distance and time
1,001 m · Snowdonia
Glyder Fawr is the highest of the Glyderau, a rocky plateau above Llyn Idwal reached by the steep path past the Devil's Kitchen.
A hard mountain walk to the summit from Afon Las mapped footpath entrance.
Afon Las from Nant Peris starts at about 150 m and gains 825 m over 3.5 km to 979 m on the track. It is steep from the start: the first kilometre climbs 363 m (36%). The steepest kilometre is the one ending at 1 km, which climbs 363 m at an average of 36%, with a 500 m stretch from 0.4 km at about 43%. It keeps climbing at 21% to the top. About 60% of the way is steeper than 1 in 5, so expect hands-on-knees going and a slow descent.
Afon Las from Nant Peris at a glance
| Distance | 3.5 km one way, to the top |
|---|---|
| Ascent | 860 m |
| Climb on the track | 825 m up, 0 m down on the way |
| Start and top of the track | 150 m to 980 m (summit 1,001 m) |
| Steepest 500 m | About 43%, from 0.4 km |
| Steeper than 1 in 5 | 60% of the way |
| Time up | 2h 10m by Naismith's rule |
| There and back | 2h 50m, down the same way |
| Grade | Hard |
| Start | Afon Las mapped footpath entrance, LL55 4UF |
| Start grid reference | SH 615 577 |
| Summit grid reference | SH 642 579 |
| Parking | Nant Peris park and ride car park; the postcode is approximate |
Afon Las from Nant Peris map
The track from the start (green) to the summit (blue), with a marker at each kilometre.
Height profile and getting to the start
Near the start
From OpenStreetMap, within 2 km. Check opening times before you rely on them.
Download the Afon Las from Nant Peris GPX
Ascent only: plan your way down. A planning track, not checked on the ground; it doesn't show safe scrambling moves. Track data © OpenStreetMap contributors (ODbL), heights from a terrain model.
Afon Las from Nant Peris kilometre by kilometre
Height, climb and average gradient for each kilometre of the track, with a grid reference at the end of each one to check your position on the map.
| At | Height | Climb | Gradient | Grid ref |
|---|---|---|---|---|
| 1 km | 513 m | +363 m | 36% steep | SH 623 580 |
| 2 km | 706 m | +193 m | 19% | SH 632 584 |
| 3 km | 870 m | +164 m | 16% | SH 638 581 |
| 3.5 km | 979 m | +109 m | 21% steep | SH 642 579 |
How long Afon Las from Nant Peris takes
| Pace | To the top | There and back |
|---|---|---|
| Brisk 6 km/h, 8 min per 100 m up | 1h 45m | 2h 20m |
| Steady (Naismith) 5 km/h, 10 min per 100 m up | 2h 10m | 2h 50m |
| Relaxed 4 km/h, 12 min per 100 m up | 2h 35m | 3h 30m |
Times leave out stops. Coming down the same way, the table counts the ascent once; steep descents on rough ground can be as slow as the climb.
- Today: sunrise 07:48, sunset 18:14. Start by 14:24 to be down before dark, allowing 2h 50m for the walk and an hour for stops.
- Tomorrow: sunrise 07:50, sunset 18:12. Start by 14:22 to be down before dark, allowing 2h 50m for the walk and an hour for stops.
Glyder Fawr summit weather for this route
-
Good Today Sunday 18 October
Overcast, up to 5°C at the summit, feeling as cold as -5°C, summit wind 24 mph gusting 30 mph, 0% chance of rain. Rated Good. Sunrise 07:48, sunset 18:14.
-
Poor Tomorrow Monday 19 October
Moderate drizzle, up to 6°C at the summit, feeling as cold as -3°C, summit wind 43 mph gusting 53 mph, 90% chance of rain. Rated Poor. Sunrise 07:50, sunset 18:12.
Best day of the next seven for Afon Las from Nant Peris: Sunday 18 October, with summit gusts around 30 mph and a 0% chance of rain.
Cloud inversion tomorrow morning: 0% (Low), best around 04:00. 7-day inversion outlook.
Hour-by-hour Glyder Fawr forecast · 14-day forecast · Is it safe to climb Glyder Fawr?
Before you go, also check: MWIS Snowdonia forecast · Met Office mountain forecast.
What to take today
- An insulated jacket, hat and warm gloves: it feels like -5°C on top.
- A waterproof jacket. It can rain on the tops in any forecast.
- Microspikes for icy paths. In snow, an ice axe and crampons and the skills to use them.
- Map and compass, and the skills to use them. A phone is a backup, not a plan.
- A head torch, food, water, a charged phone and a small first aid kit.
About Glyder Fawr
Glyder Fawr is the highest of the Glyderau, a rocky plateau above Llyn Idwal reached by the steep path past the Devil's Kitchen. More about Glyder Fawr, with the live forecast.
On the lists: Furth, Hewitt, Nuttall, Marilyn.
Extend the walk: tops near the summit
- Castell y Gwynt (972 m), 1.2 km east
- Glyder Fach (994 m), 1.4 km east
- Y Garn (947 m), 2 km north-west
- Tryfan (918 m), 2.6 km north-east
Challenges that include Glyder Fawr
- Welsh 3000s · 15
- Welsh 100 Challenge · 100
- Welsh 1000m Peaks · 5
- Snowdonia 900m Peaks · 16
- Welsh Skyline · 9
- Paddy Buckley Round · 47
- Furths · 34
- Hewitts · 523
- Nuttalls · 442
- Marilyns · 1,555
More walks from Afon Las mapped footpath entrance
Routes in Peakify's guides that start within 500 m of this one, for another day from the same car park.
- Afon Las from Nant Peris and plateau traverse up Glyder Fach
- Llwybr y Carw / Afon Las up Y Garn
Other routes up Glyder Fawr
| Route | Distance | Ascent | Time up | Grade |
|---|---|---|---|---|
| Pen y Pass | 3.1 km one way | 630 m | 1h 40m | Moderate |
| Ogwen via the Devil's Kitchen | 4.9 km one way | 890 m | 2h 30m | Hard |
| Devil's Kitchen / Twll Du | 3.9 km one way | 720 m | 2h 0m | Hard |
| Miners' Track from Pen-y-Gwryd and plateau traverse | 5.5 km one way | 780 m | 2h 25m | Hard |
| Senior's Gully and Ridge | 4.6 km one way | 830 m | 2h 20m | Scramble |
| Y Gribin | 4.0 km one way | 720 m | 2h 0m | Scramble |
| Bristly Ridge and plateau traverse | 4.6 km one way | 760 m | 2h 10m | Scramble |
In an emergency
Call 999, ask for the police and then mountain rescue. Give your location (the start is at SH 615 577, the summit at SH 642 579), what happened and how many are in your group. If you have no signal for a call, a text to 999 works once you have registered your phone with emergencySMS: text "register" to 999 before you go.
Afon Las from Nant Peris: questions and answers
How far is Afon Las from Nant Peris?
Afon Las from Nant Peris is 3.5 km one way to the summit of Glyder Fawr, with 860 m of ascent. There and back by the same way is about 7.0 km.
How long does Afon Las from Nant Peris take?
About 2h 10m to the summit of Glyder Fawr and 2h 50m there and back by Naismith's rule (5 km/h plus 10 minutes per 100 m of ascent), before stops. A relaxed group takes nearer 3h 30m for the round trip.
How steep is Afon Las from Nant Peris?
The steepest 500 m averages about 43%, starting 0.4 km from the start, and 60% of the way is steeper than 1 in 5. Afon Las from Nant Peris climbs 825 m in all on the track.
Where do you park for Afon Las from Nant Peris?
Afon Las from Nant Peris starts from Afon Las mapped footpath entrance (postcode LL55 4UF). The grid reference is SH 615 577. Nant Peris park and ride car park; the postcode is approximate
Is Afon Las from Nant Peris suitable for beginners?
Not as a first mountain. Peakify grades it Hard: steep, rough ground where a slip matters. Build up on an easier route first, such as Pen y Pass.
What time should I start Afon Las from Nant Peris today?
By 14:24 at the latest. Sunset on Glyder Fawr today is 18:14, Afon Las from Nant Peris takes about 2h 50m there and back, and that leaves an hour for stops. Start earlier in winter or if the forecast turns.
Is there a GPX for Afon Las from Nant Peris?
Yes. Download it from this page. It is an ascent-only planning track from the start to the summit, plotted on OpenStreetMap paths and not checked on the ground.