Treharris Weather Forecast

    • 3
    • 5

    Overcast

    • -1
    • 5

    Cloudy

    • -1
    • 4

    Cloudy

    • 1
    • 5

    Overcast

    • -2
    • 4

    Sunny day

    • -3
    • 3

    Sunny day

    • -3
    • 2

    Sunny day

Today 29 Dec Wales

Remaining rather cloudy, with the best of the brightness in the west. Cloud thick enough over the hills for some drizzle, but most places remaining dry. Fairly light winds but feeling chilly after a cold start. Maximum Temperature 7C.

Tonight 29 Dec Wales

Remaining largely cloudy by dry this evening and overnight with clearer spells developing by dawn in the east. Turning chilly in places with a touch of frost in rural spots and under the lengthiest clear skies. Minimum Temperature -1C.

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Treharris Temperature Statistics

December Temperature

St-athan (30km)

  • Lowest 17 December, 2025

    1 °C

  • Average December

    8.6 °C

  • Highest 9 December, 2025

    15.2 °C

Climate (2020–Present)

St-athan (30km)

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  • Average Low 2020–2025

    8.8 °C

  • Average 2020–2025

    11.7 °C

  • Average High 2020–2025

    14.5 °C
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