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Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Metro Report weather desk. Data from national met services via Open-Meteo.
Live data from Open-Meteo · updates automatically ·
The live forecast above shows the current conditions in Mountain Ash, the former mining town in the Cynon Valley, Rhondda Cynon Taf. For the rest of the week, expect cloud building from the coast with patchy light rain, typical of this inland valley setting.
What is the weather like in Mountain Ash today?
The live forecast above gives the immediate picture for Mountain Ash. Because the town sits in a deep, north–south valley in the South Wales Coalfield, it often traps low cloud and mist long after the coast has cleared. The Brecon Beacons to the north block some frontal systems, but Atlantic weather systems still bring regular spells of rain, especially in autumn and winter. For the most accurate minute‑by‑minute update, also check BBC Weather Mountain Ash and Met Office Weather Mountain Ash — both services are referenced in the live data above.
How does the valley location affect the forecast?
Mountain Ash lies about 20 miles north of Cardiff, but its enclosed valley means temperatures can be a degree or two cooler than the coastal plain. Frost and fog form more readily on clear, calm nights, while summer afternoons often feel pleasantly warm once the sun burns off any early cloud. The Cynon River runs through the town, adding local humidity. If you are planning ahead, the 10 Day Weather Forecast UK page gives a reliable outlook for this valley, and the UK weather hub links to wider regional trends.
Does Mountain Ash get more rain than Cardiff?
Yes, on average. The valley funnels moisture from prevailing south‑westerly winds, and the surrounding hills cause orographic lift. Expect about 10–15% more annual rainfall than Cardiff city centre.
What is the weather in Mountain Ash tomorrow?
The live forecast above updates with the latest model for tomorrow. Typically, if high pressure builds, the valley can stay cloudy while nearby hilltops remain clear. For a precise look, refer to the Bristol Weather page, which often mirrors coastal trends that affect the valley.
Is there a flood risk in Mountain Ash?
The Cynon River can rise quickly after heavy, prolonged rain. The Met Office issues flood alerts for the valley when needed. Always check the latest warnings on GOV.UK during persistent wet spells.