Cwm Nantcol western approach 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 Cil-cychwyn public path.
Cwm Nantcol western approach starts at about 175 m and gains 561 m over 4.8 km to 741 m on the track. The first kilometre climbs 80 m. The steepest kilometre is the one ending at 2 km, which climbs 151 m at an average of 15%. It keeps climbing at 13% to the top.
Cwm Nantcol western approach at a glance
| Distance | 4.8 km one way, to the top |
|---|---|
| Ascent | 580 m |
| Climb on the track | 561 m up, 0 m down on the way |
| Start and top of the track | 176 m to 741 m (summit 756 m) |
| Steepest 500 m | About 18%, from 0.9 km |
| Steeper than 1 in 5 | 6% of the way |
| Time up | 1h 55m by Naismith's rule |
| There and back | 2h 55m, down the same way |
| Grade | Hard |
| Start | Cil-cychwyn public path |
| Start grid reference | SH 634 260 |
| Summit grid reference | SH 661 257 |
| Parking | No checked car park for this start; find lawful parking nearby |
Cwm Nantcol western approach 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 Cwm Nantcol western approach 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.
Cwm Nantcol western approach 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 | 255 m | +80 m | 8% | SH 636 256 |
| 2 km | 406 m | +151 m | 15% | SH 640 250 |
| 3 km | 518 m | +113 m | 11% | SH 645 252 |
| 4 km | 636 m | +117 m | 12% | SH 655 253 |
| 4.8 km | 741 m | +105 m | 13% | SH 661 257 |
How long Cwm Nantcol western approach takes
| Pace | To the top | There and back |
|---|---|---|
| Brisk 6 km/h, 8 min per 100 m up | 1h 35m | 2h 20m |
| Steady (Naismith) 5 km/h, 10 min per 100 m up | 1h 55m | 2h 55m |
| Relaxed 4 km/h, 12 min per 100 m up | 2h 20m | 3h 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 14:17 to be down before dark, allowing 2h 55m for the walk and an hour for stops.
- Tomorrow: sunrise 07:51, sunset 18:10. Start by 14:15 to be down before dark, allowing 2h 55m for the walk and an hour for stops.
Y Llethr summit weather for this route
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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 Cwm Nantcol western approach: 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 Cil-cychwyn public path
Routes in Peakify's guides that start within 500 m of this one, for another day from the same car park.
- Cwm Nantcol via Y Llethr and Crib-y-rhiw up Diffwys
Other routes up Y Llethr
| Route | Distance | Ascent | Time up | Grade |
|---|---|---|---|---|
| Graigddu-isaf via Rhinog Fach | 6.6 km one way | 660 m | 2h 25m | 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 634 260, 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.
Cwm Nantcol western approach: questions and answers
How far is Cwm Nantcol western approach?
Cwm Nantcol western approach is 4.8 km one way to the summit of Y Llethr, with 580 m of ascent. There and back by the same way is about 9.6 km.
How long does Cwm Nantcol western approach take?
About 1h 55m to the summit of Y Llethr and 2h 55m 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 35m for the round trip.
How steep is Cwm Nantcol western approach?
The steepest 500 m averages about 18%, starting 0.9 km from the start, and 6% of the way is steeper than 1 in 5. Cwm Nantcol western approach climbs 561 m in all on the track.
Where do you park for Cwm Nantcol western approach?
Cwm Nantcol western approach starts from Cil-cychwyn public path. The grid reference is SH 634 260. No checked car park for this start; find lawful parking nearby
Is Cwm Nantcol western approach 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 Cwm Nantcol western approach today?
By 14:17 at the latest. Sunset on Y Llethr today is 18:12, Cwm Nantcol western approach takes about 2h 55m there and back, and that leaves an hour for stops. Start earlier in winter or if the forecast turns.
Is there a GPX for Cwm Nantcol western approach?
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.