The name Pen-twyn comes from Welsh: "pen" (head/top/summit) + "twyn" (sand dune/hillock) — roughly "head of the sand dune".
Pen-twyn is a 105m (344ft) Wales hill classified as a Tump (100-199m), one of 3478 Tump (100-199m)s in Wales. Check the Pen-twyn weather forecast for wind, rain and visibility before your walk. Even at lower elevations, hill weather can differ significantly from the valley.
Geology: The bedrock here is Moor Cliffs Formation — Siltstone and mudstone, interbedded — a fine-grained sedimentary rock formed from compressed mud and clay. Age: Pridoli Epoch.
Planning to walk Pen-twyn? Our summit weather forecast shows live conditions at 105m including wind speed, wind chill, temperature, freezing level, cloud base and rain risk. The forecast updates hourly using data from 7 weather models blended into the HILLANDGLEN ensemble — accuracy-weighted so the best-performing models have the most influence.
Key conditions to check before climbing Pen-twyn: wind chill (the real temperature you'll feel on exposed ridges), freezing level (whether ice and snow are likely on the summit), cloud base (whether you'll have visibility at 105m), and wind gusts (which can be significantly stronger on exposed summits than in the valley below).
Pen-twyn weather can change quickly. Valley conditions often differ from the summit — our forecast applies lapse rate adjustments to give you the actual temperature and wind at the top, not the nearest town. Check the 14-day outlook to find the best day to walk Pen-twyn.
Frequently Asked Questions
How high is Pen-twyn?
Pen-twyn is 105 metres (344 feet) above sea level. It is classified as a Tump (100-199m) in Wales.
What is the weather like on Pen-twyn?
Pen-twyn stands at 105m, where conditions can still differ from the valley. Wind is typically stronger on the summit, and rain showers can arrive quickly in Wales. Check the hillandglen.com forecast for live summit wind, temperature and rain risk.
Is Pen-twyn suitable for beginners?
At 105m, Pen-twyn is one of the more accessible hills and is popular with walkers of all abilities. However, weather can change quickly — always check the forecast and carry waterproofs. Good footwear with grip is recommended as paths can be muddy or rocky.
When is the best time to climb Pen-twyn?
The best months for climbing Pen-twyn are typically May to September, when days are longest and weather is generally drier. Summer offers the most stable conditions and longest daylight hours. Autumn can also be excellent with clearer skies and golden light.
Free summit weather forecasts for over 20,000 British and Irish hills. Designed for hikers, runners, and climbers who need accurate mountain conditions — not just city weather.
