Graigddu-isaf via Rhinog Fach up Y Llethr: route map, distance and time
756 m · Snowdonia
Y Llethr is the 756 m high point of the Rhinogydd in southern Snowdonia, a grassy summit set among some of the roughest ground in Wales.
A hard mountain walk to the summit from Cwrt Forest / Graigddu-isaf car park.
Graigddu-isaf via Rhinog Fach starts at about 264 m and gains 638 m over 6.6 km to 741 m on the track. The first 3 km are the easy part, averaging 3%. The steepest kilometre is the one ending at 4 km, which climbs 216 m at an average of 22%, with a 500 m stretch from 3.3 km at about 34%. It keeps climbing at 11% to the top. About 20% of the way is steeper than 1 in 5, so expect hands-on-knees going and a slow descent.
Graigddu-isaf via Rhinog Fach at a glance
| Distance | 6.6 km one way, to the top |
|---|---|
| Ascent | 660 m |
| Climb on the track | 638 m up, 160 m down on the way |
| Start and top of the track | 252 m to 746 m (summit 756 m) |
| Steepest 500 m | About 34%, from 3.3 km |
| Steeper than 1 in 5 | 20% of the way |
| Time up | 2h 25m by Naismith's rule |
| There and back | 3h 45m, down the same way |
| Grade | Hard |
| Start | Cwrt Forest / Graigddu-isaf car park, LL41 4YE |
| Start grid reference | SH 684 302 |
| Summit grid reference | SH 661 257 |
| Parking | Cwrt Forest / Graigddu-isaf car park (SH684302) |
Graigddu-isaf via Rhinog Fach map
The track from the start (green) to the summit (blue), with a marker at each kilometre.
Height profile and getting to the start
Download the Graigddu-isaf via Rhinog Fach 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.
Graigddu-isaf via Rhinog Fach 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 | 261 m | -3 m | 0% | SH 679 295 |
| 2 km | 301 m | +40 m | 4% | SH 674 287 |
| 3 km | 364 m | +63 m | 6% | SH 666 282 |
| 4 km | 580 m | +216 m | 22% steep | SH 666 275 |
| 5 km | 640 m | +60 m | 6% | SH 666 268 |
| 6 km | 680 m | +40 m | 4% | SH 664 261 |
| 6.6 km | 741 m | +61 m | 11% | SH 661 257 |
How long Graigddu-isaf via Rhinog Fach takes
| Pace | To the top | There and back |
|---|---|---|
| Brisk 6 km/h, 8 min per 100 m up | 2h 0m | 3h 5m |
| Steady (Naismith) 5 km/h, 10 min per 100 m up | 2h 25m | 3h 45m |
| Relaxed 4 km/h, 12 min per 100 m up | 3h 0m | 4h 35m |
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 07:49, sunset 18:12. Start by 13:27 to be down before dark, allowing 3h 45m for the walk and an hour for stops.
- Tomorrow: sunrise 07:51, sunset 18:10. Start by 13:25 to be down before dark, allowing 3h 45m for the walk and an hour for stops.
Y Llethr summit weather for this route
-
Marginal Today Monday 19 October
Moderate drizzle, up to 7°C at the summit, feeling as cold as -2°C, summit wind 39 mph gusting 49 mph, 49% chance of rain. Rated Marginal. Sunrise 07:49, sunset 18:12.
-
Good Tomorrow Tuesday 20 October
Fog, up to 9°C at the summit, feeling as cold as -4°C, summit wind 24 mph gusting 30 mph, 57% chance of rain. Rated Good. Sunrise 07:51, sunset 18:10.
Best day of the next seven for Graigddu-isaf via Rhinog Fach: Tuesday 20 October, with summit gusts around 30 mph and a 57% chance of rain.
Hour-by-hour Y Llethr forecast
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 -2°C on top.
- Waterproof jacket and overtrousers: 49% chance of rain.
- A windproof layer, and poles for balance in gusts to 49 mph.
- 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 Llethr
Y Llethr is the 756 m high point of the Rhinogydd in southern Snowdonia, a grassy summit set among some of the roughest ground in Wales. More about Y Llethr, with the live forecast.
On the lists: Hewitt, Nuttall, Marilyn.
Extend the walk: tops near the summit
- Crib-y-rhiw (681 m), 0.9 km south
- Rhinog Fach (712 m), 1.3 km north
- Diffwys (750 m), 2.4 km south
Challenges that include Y Llethr
More walks from Cwrt Forest / Graigddu-isaf car park
Routes in Peakify's guides that start within 500 m of this one, for another day from the same car park.
- Graigddu-isaf via Llyn Du up Rhinog Fawr
- Graigddu-isaf via Bwlch Drws Ardudwy up Rhinog Fach
Other routes up Y Llethr
| Route | Distance | Ascent | Time up | Grade |
|---|---|---|---|---|
| Cwm Nantcol western approach | 4.8 km one way | 580 m | 1h 55m | Hard |
| Cwm Mynach via Diffwys and Crib-y-rhiw | 7.0 km one way | 720 m | 2h 35m | Hard |
In an emergency
Call 999, ask for the police and then mountain rescue. Give your location (the start is at SH 684 302, the summit at SH 661 257), 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.
Graigddu-isaf via Rhinog Fach: questions and answers
How far is Graigddu-isaf via Rhinog Fach?
Graigddu-isaf via Rhinog Fach is 6.6 km one way to the summit of Y Llethr, with 660 m of ascent. There and back by the same way is about 13.2 km.
How long does Graigddu-isaf via Rhinog Fach take?
About 2h 25m to the summit of Y Llethr and 3h 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 4h 35m for the round trip.
How steep is Graigddu-isaf via Rhinog Fach?
The steepest 500 m averages about 34%, starting 3.3 km from the start, and 20% of the way is steeper than 1 in 5. Graigddu-isaf via Rhinog Fach climbs 638 m in all on the track.
Where do you park for Graigddu-isaf via Rhinog Fach?
Graigddu-isaf via Rhinog Fach starts from Cwrt Forest / Graigddu-isaf car park (postcode LL41 4YE). The grid reference is SH 684 302. Cwrt Forest / Graigddu-isaf car park (SH684302)
Is Graigddu-isaf via Rhinog Fach 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 Graigddu-isaf via Rhinog Fach today?
By 13:27 at the latest. Sunset on Y Llethr today is 18:12, Graigddu-isaf via Rhinog Fach takes about 3h 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 Graigddu-isaf via Rhinog Fach?
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.