Graigddu-isaf via Llyn Du up Rhinog Fawr: route map, distance and time
720 m · Snowdonia
Rhinog Fawr is a rough, heathery mountain in the Rhinogydd, climbed from Cwm Bychan by the Roman Steps.
A hard mountain walk to the summit from Cwrt Forest / Graigddu-isaf car park.
Graigddu-isaf via Llyn Du starts at about 265 m and gains 447 m over 4.3 km to 700 m on the track. The first 3 km are the easy part, averaging 6%. The steepest kilometre is the one ending at 4.3 km, which climbs 78 m at an average of 30%. That last pull ends at the summit. About 17% of the way is steeper than 1 in 5, so expect hands-on-knees going and a slow descent.
Graigddu-isaf via Llyn Du at a glance
| Distance | 4.3 km one way, to the top |
|---|---|
| Ascent | 480 m |
| Climb on the track | 447 m up, 15 m down on the way |
| Start and top of the track | 252 m to 700 m (summit 720 m) |
| Steepest 500 m | About 32%, from 3.7 km |
| Steeper than 1 in 5 | 17% of the way |
| Time up | 1h 40m by Naismith's rule |
| There and back | 2h 30m, 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 656 290 |
| Parking | Cwrt Forest / Graigddu-isaf car park (SH684302) |
Graigddu-isaf via Llyn Du 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 Llyn Du 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 Llyn Du 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 | 267 m | +2 m | 0% | SH 676 298 |
| 2 km | 333 m | +66 m | 7% | SH 667 297 |
| 3 km | 447 m | +114 m | 11% | SH 660 296 |
| 4 km | 622 m | +176 m | 18% | SH 655 291 |
| 4.3 km | 700 m | +78 m | 30% steep | SH 656 290 |
How long Graigddu-isaf via Llyn Du takes
| Pace | To the top | There and back |
|---|---|---|
| Brisk 6 km/h, 8 min per 100 m up | 1h 20m | 2h 5m |
| Steady (Naismith) 5 km/h, 10 min per 100 m up | 1h 40m | 2h 30m |
| Relaxed 4 km/h, 12 min per 100 m up | 2h 0m | 3h 5m |
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 07:47, sunset 18:14. Start by 14:44 to be down before dark, allowing 2h 30m for the walk and an hour for stops.
- Tomorrow: sunrise 07:49, sunset 18:12. Start by 14:42 to be down before dark, allowing 2h 30m for the walk and an hour for stops.
Rhinog Fawr summit weather for this route
There is no recent summit forecast cached for Rhinog Fawr right now. The main Rhinog Fawr page loads the live forecast when you open it. Open the live Rhinog Fawr forecast.
Before you go, also check: MWIS Snowdonia forecast · Met Office mountain forecast.
About Rhinog Fawr
Rhinog Fawr is a rough, heathery mountain in the Rhinogydd, climbed from Cwm Bychan by the Roman Steps. More about Rhinog Fawr, with the live forecast.
On the lists: Hewitt, Nuttall, Marilyn.
Extend the walk: tops near the summit
- Rhinog Fach (712 m), 2.1 km south-east
Challenges that include Rhinog Fawr
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 Rhinog Fach up Y Llethr
- Graigddu-isaf via Bwlch Drws Ardudwy up Rhinog Fach
Other routes up Rhinog Fawr
| Route | Distance | Ascent | Time up | Grade |
|---|---|---|---|---|
| Cwm Bychan via the Roman Steps | 4.0 km one way | 580 m | 1h 45m | Hard |
| Cwm Nantcol western approach | 8.8 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 684 302, the summit at SH 656 290), 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 Llyn Du: questions and answers
How far is Graigddu-isaf via Llyn Du?
Graigddu-isaf via Llyn Du is 4.3 km one way to the summit of Rhinog Fawr, with 480 m of ascent. There and back by the same way is about 8.6 km.
How long does Graigddu-isaf via Llyn Du take?
About 1h 40m to the summit of Rhinog Fawr and 2h 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 3h 5m for the round trip.
How steep is Graigddu-isaf via Llyn Du?
The steepest 500 m averages about 32%, starting 3.7 km from the start, and 17% of the way is steeper than 1 in 5. Graigddu-isaf via Llyn Du climbs 447 m in all on the track.
Where do you park for Graigddu-isaf via Llyn Du?
Graigddu-isaf via Llyn Du 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 Llyn Du 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 Llyn Du today?
By 14:44 at the latest. Sunset on Rhinog Fawr today is 18:14, Graigddu-isaf via Llyn Du takes about 2h 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 Graigddu-isaf via Llyn Du?
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.