Marchlyn via Elidir Fawr and Mynydd Perfedd up Y Garn (Snowdonia): route map, distance and time
947 m · Snowdonia
Y Garn is a pointed Glyderau summit above Llyn Idwal, with a classic view down to the Ogwen valley and Tryfan.
A hard mountain walk to the summit from Marchlyn public road end (SH596631).
Marchlyn via Elidir Fawr and Mynydd Perfedd starts at about 362 m and gains 831 m over 7.6 km to 913 m on the track. The first kilometre climbs 101 m. The steepest kilometre is the one ending at 2 km, which climbs 251 m at an average of 25%, with a 500 m stretch from 1.4 km at about 33%. It keeps climbing at 20% to the top. About 21% of the way is steeper than 1 in 5, so expect hands-on-knees going and a slow descent.
Marchlyn via Elidir Fawr and Mynydd Perfedd at a glance
| Distance | 7.6 km one way, to the top |
|---|---|
| Ascent | 870 m |
| Climb on the track | 831 m up, 282 m down on the way |
| Start and top of the track | 362 m to 913 m (summit 947 m) |
| Steepest 500 m | About 33%, from 1.4 km |
| Steeper than 1 in 5 | 21% of the way |
| Time up | 3h 0m by Naismith's rule |
| There and back | 4h 30m, down the same way |
| Grade | Hard |
| Start | Marchlyn public road end (SH596631) |
| Start grid reference | SH 596 630 |
| Summit grid reference | SH 630 595 |
| Parking | No checked car park for this start; find lawful parking nearby |
Marchlyn via Elidir Fawr and Mynydd Perfedd 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 Marchlyn via Elidir Fawr and Mynydd Perfedd 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.
Marchlyn via Elidir Fawr and Mynydd Perfedd 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 | 463 m | +101 m | 10% | SH 605 627 |
| 2 km | 714 m | +251 m | 25% steep | SH 605 619 |
| 3 km | 793 m | +79 m | 8% | SH 607 613 |
| 4 km | 814 m | +21 m | 2% | SH 616 613 |
| 5 km | 785 m | -28 m | -3% | SH 623 617 |
| 6 km | 745 m | -41 m | -4% | SH 626 609 |
| 7 km | 797 m | +52 m | 5% | SH 627 599 |
| 7.6 km | 913 m | +116 m | 20% steep | SH 630 595 |
How long Marchlyn via Elidir Fawr and Mynydd Perfedd takes
| Pace | To the top | There and back |
|---|---|---|
| Brisk 6 km/h, 8 min per 100 m up | 2h 25m | 3h 40m |
| Steady (Naismith) 5 km/h, 10 min per 100 m up | 3h 0m | 4h 30m |
| Relaxed 4 km/h, 12 min per 100 m up | 3h 40m | 5h 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 12:44 to be down before dark, allowing 4h 30m for the walk and an hour for stops.
- Tomorrow: sunrise 07:50, sunset 18:12. Start by 12:42 to be down before dark, allowing 4h 30m for the walk and an hour for stops.
Y Garn 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, 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 -2°C, summit wind 43 mph gusting 54 mph, 90% chance of rain. Rated Poor. Sunrise 07:50, sunset 18:12.
Best day of the next seven for Marchlyn via Elidir Fawr and Mynydd Perfedd: Sunday 18 October, with summit gusts around 30 mph and a 0% chance of rain.
Cloud inversion tomorrow morning: 1% (Low), best around 06:00. 7-day inversion outlook.
Hour-by-hour Y Garn forecast · 14-day forecast · Is it safe to climb Y Garn?
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.
- 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 Y Garn
Y Garn is a pointed Glyderau summit above Llyn Idwal, with a classic view down to the Ogwen valley and Tryfan. More about Y Garn, with the live forecast.
On the lists: Furth, Hewitt, Nuttall, Marilyn.
Extend the walk: tops near the summit
- Foel-goch (831 m), 1.7 km north
- Glyder Fawr (1,001 m), 2 km south-east
- Mynydd Perfedd (813 m), 2.4 km north
- Elidir Fawr (924 m), 2.6 km north-west
- Castell y Gwynt (972 m), 2.7 km south-east
- Glyder Fach (994 m), 2.9 km south-east
Challenges that include Y Garn
- 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 Marchlyn public road end
Routes in Peakify's guides that start within 500 m of this one, for another day from the same car park.
- Marchlyn via Elidir Fach up Elidir Fawr
- Marchlyn via Mynydd Perfedd up Elidir Fawr
- Marchlyn mountain-road approach up Carnedd y Filiast
- Marchlyn mountain-road approach up Mynydd Perfedd
- Marchlyn mountain-road approach up Foel-goch
Other routes up Y Garn
| Route | Distance | Ascent | Time up | Grade |
|---|---|---|---|---|
| Ogwen via Llyn Clyd | 4.4 km one way | 741 m | 2h 5m | Hard |
| North East Ridge | 2.6 km one way | 640 m | 1h 35m | Hard |
| Devil's Kitchen / Twll Du | 4.3 km one way | 670 m | 2h 0m | Hard |
| Llwybr y Carw / Afon Las | 3.6 km one way | 800 m | 2h 5m | Hard |
| Elidir Fawr, Mynydd Perfedd and Foel-goch | 7.5 km one way | — | — | Hard |
In an emergency
Call 999, ask for the police and then mountain rescue. Give your location (the start is at SH 596 630, the summit at SH 630 595), 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.
Marchlyn via Elidir Fawr and Mynydd Perfedd: questions and answers
How far is Marchlyn via Elidir Fawr and Mynydd Perfedd?
Marchlyn via Elidir Fawr and Mynydd Perfedd is 7.6 km one way to the summit of Y Garn, with 870 m of ascent. There and back by the same way is about 15.2 km.
How long does Marchlyn via Elidir Fawr and Mynydd Perfedd take?
About 3h 0m to the summit of Y Garn and 4h 30m 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 5h 30m for the round trip.
How steep is Marchlyn via Elidir Fawr and Mynydd Perfedd?
The steepest 500 m averages about 33%, starting 1.4 km from the start, and 21% of the way is steeper than 1 in 5. Marchlyn via Elidir Fawr and Mynydd Perfedd climbs 831 m in all on the track.
Where do you park for Marchlyn via Elidir Fawr and Mynydd Perfedd?
Marchlyn via Elidir Fawr and Mynydd Perfedd starts from Marchlyn public road end (SH596631). The grid reference is SH 596 630. No checked car park for this start; find lawful parking nearby
Is Marchlyn via Elidir Fawr and Mynydd Perfedd 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.
What time should I start Marchlyn via Elidir Fawr and Mynydd Perfedd today?
By 12:44 at the latest. Sunset on Y Garn today is 18:14, Marchlyn via Elidir Fawr and Mynydd Perfedd takes about 4h 30m there and back, and that leaves an hour for stops. Start earlier in winter or if the forecast turns.
Is there a GPX for Marchlyn via Elidir Fawr and Mynydd Perfedd?
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.