Nant Peris via the Afon Dudodyn up Elidir Fawr: route map, distance and time
924 m · Snowdonia
Elidir Fawr is the western end of the Glyderau in Snowdonia, a large mountain above the Dinorwig quarries and the reservoir of Marchlyn Mawr.
A path beside the Afon Dudodyn, then steep, grassy slopes to the ridge and the summit.
Nant Peris via the Afon Dudodyn starts at about 113 m and gains 775 m over 3.4 km to 888 m on the track. The first kilometre climbs 118 m. The steepest kilometre is the one ending at 3 km, which climbs 307 m at an average of 31%. It keeps climbing at 26% to the top. About 65% of the way is steeper than 1 in 5, so expect hands-on-knees going and a slow descent.
Nant Peris via the Afon Dudodyn at a glance
| Distance | 3.4 km one way, to the top |
|---|---|
| Ascent | 810 m |
| Climb on the track | 775 m up, 0 m down on the way |
| Start and top of the track | 112 m to 890 m (summit 924 m) |
| Steepest 500 m | About 34%, from 2.8 km |
| Steeper than 1 in 5 | 65% of the way |
| Time up | 2h 0m by Naismith's rule |
| There and back | 2h 45m, down the same way |
| Grade | Moderate |
| Start | Nant Peris public approach lane, LL55 4UF |
| Start grid reference | SH 605 584 |
| Summit grid reference | SH 611 612 |
| Parking | Nant Peris park and ride car park; the postcode is approximate |
Nant Peris via the Afon Dudodyn 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 Nant Peris via the Afon Dudodyn 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.
Nant Peris via the Afon Dudodyn 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 | 231 m | +118 m | 12% | SH 606 592 |
| 2 km | 470 m | +239 m | 24% steep | SH 609 600 |
| 3 km | 777 m | +307 m | 31% steep | SH 611 609 |
| 3.4 km | 888 m | +111 m | 26% steep | SH 611 613 |
How long Nant Peris via the Afon Dudodyn takes
| Pace | To the top | There and back |
|---|---|---|
| Brisk 6 km/h, 8 min per 100 m up | 1h 40m | 2h 15m |
| Steady (Naismith) 5 km/h, 10 min per 100 m up | 2h 0m | 2h 45m |
| Relaxed 4 km/h, 12 min per 100 m up | 2h 30m | 3h 20m |
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 14:29 to be down before dark, allowing 2h 45m for the walk and an hour for stops.
- Tomorrow: sunrise 07:50, sunset 18:12. Start by 14:27 to be down before dark, allowing 2h 45m for the walk and an hour for stops.
Elidir Fawr summit weather for this route
-
Good Today Sunday 18 October
Overcast, up to 5°C at the summit, feeling as cold as -4°C, summit wind 24 mph gusting 30 mph, 21% chance of rain. Rated Good. Sunrise 07:48, sunset 18:14.
-
Marginal Tomorrow Monday 19 October
Moderate drizzle, up to 6°C at the summit, feeling as cold as -1°C, summit wind 39 mph gusting 49 mph, 73% chance of rain. Rated Marginal. Sunrise 07:50, sunset 18:12.
Best day of the next seven for Nant Peris via the Afon Dudodyn: Sunday 18 October, with summit gusts around 30 mph and a 21% chance of rain.
Cloud inversion tomorrow morning: 3% (Low), best around 05:00. 7-day inversion outlook.
Hour-by-hour Elidir Fawr forecast · 14-day forecast · Is it safe to climb Elidir 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 -4°C on top.
- A waterproof jacket. It can rain on the tops in any forecast.
- A windproof layer, and poles for balance in gusts to 30 mph.
- 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 Elidir Fawr
Elidir Fawr is the western end of the Glyderau in Snowdonia, a large mountain above the Dinorwig quarries and the reservoir of Marchlyn Mawr. More about Elidir Fawr, with the live forecast.
On the lists: Furth, Hewitt, Nuttall, Marilyn.
Extend the walk: tops near the summit
- Mynydd Perfedd (813 m), 1.3 km north-east
- Carnedd y Filiast (821 m), 1.7 km north-east
- Foel-goch (831 m), 1.7 km east
- Carnedd y Filiast North Top (720 m), 2 km north
- Y Garn (947 m), 2.6 km south-east
Challenges that include Elidir Fawr
- Welsh 3000s · 15
- Welsh 100 Challenge · 100
- Snowdonia 900m Peaks · 16
- Welsh Skyline · 9
- Paddy Buckley Round · 47
- Furths · 34
- Hewitts · 523
- Nuttalls · 442
- Marilyns · 1,555
More walks from Nant Peris public approach lane
Routes in Peakify's guides that start within 500 m of this one, for another day from the same car park.
- Elidir Fawr, Mynydd Perfedd and Foel-goch up Y Garn
- Nant Peris via Elidir Fawr up Carnedd y Filiast
- Nant Peris via Elidir Fawr up Mynydd Perfedd
- Nant Peris via Elidir Fawr up Foel-goch
Other routes up Elidir Fawr
| Route | Distance | Ascent | Time up | Grade |
|---|---|---|---|---|
| Marchlyn via Elidir Fach | 3.5 km one way | 560 m | 1h 40m | Hard |
| Marchlyn via Mynydd Perfedd | 5.9 km one way | 670 m | 2h 20m | Hard |
| Ogwen via Y Garn and Mynydd Perfedd | 6.6 km one way | 920 m | 2h 50m | Hard |
In an emergency
Call 999, ask for the police and then mountain rescue. Give your location (the start is at SH 605 584, the summit at SH 611 612), 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.
Nant Peris via the Afon Dudodyn: questions and answers
How far is Nant Peris via the Afon Dudodyn?
Nant Peris via the Afon Dudodyn is 3.4 km one way to the summit of Elidir Fawr, with 810 m of ascent. There and back by the same way is about 6.8 km.
How long does Nant Peris via the Afon Dudodyn take?
About 2h 0m to the summit of Elidir Fawr and 2h 45m 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 20m for the round trip.
How steep is Nant Peris via the Afon Dudodyn?
The steepest 500 m averages about 34%, starting 2.8 km from the start, and 65% of the way is steeper than 1 in 5. Nant Peris via the Afon Dudodyn climbs 775 m in all on the track.
Where do you park for Nant Peris via the Afon Dudodyn?
Nant Peris via the Afon Dudodyn starts from Nant Peris public approach lane (postcode LL55 4UF). The grid reference is SH 605 584. Nant Peris park and ride car park; the postcode is approximate
Is Nant Peris via the Afon Dudodyn suitable for beginners?
Yes, for fit walkers on a clear day. Peakify grades it Moderate: a long climb on a made path, but the top is high, exposed and colder than the start. Turn back if the cloud comes down and you can't navigate.
What time should I start Nant Peris via the Afon Dudodyn today?
By 14:29 at the latest. Sunset on Elidir Fawr today is 18:14, Nant Peris via the Afon Dudodyn takes about 2h 45m there and back, and that leaves an hour for stops. Start earlier in winter or if the forecast turns.
Is there a GPX for Nant Peris via the Afon Dudodyn?
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.