Treharris Weather Forecast, Merthyr Tydfil CF46 5

Today 6 Dec Wales

An unsettled day, with frequent showers feeding in from the west, these often heavy and accompanied by strong gusting winds, though some sunny spells possible, primarily in the south. Continuous strong winds for exposed coastal regions and high ground. Maximum Temperature 12C.

Tonight 6 Dec Wales

Showers continue to fade through the evening, allowing clear skies to develop and winds to briefly ease. However, turning increasingly cloudy with winds strengthening again as a band of heavy rain pushes northeastwards through the early hours. Minimum Temperature 8C.

Sun 7 Dec Wales

A damp and cloudy start, as a band of rain continues to spread northeastwards through much of the day, bringing heavy and prolonged bursts. Strong winds persist for coastal regions. Maximum Temperature 14C.

Mon 8 Dec Wales

A brighter day on Monday, though occasional blustery showers likely. A heavy rain band brings wet and windy conditions on Tuesday, with coastal gales possible. Turning showery again on Wednesday.

Tue 9 Dec Wales

A brighter day on Monday, though occasional blustery showers likely. A heavy rain band brings wet and windy conditions on Tuesday, with coastal gales possible. Turning showery again on Wednesday.

Wed 10 Dec Wales

A brighter day on Monday, though occasional blustery showers likely. A heavy rain band brings wet and windy conditions on Tuesday, with coastal gales possible. Turning showery again on Wednesday.

Thu 11 Dec Wales

A continuation of a similar pattern to that seen through early December is anticipated, especially at first, as frontal systems from the Atlantic spread into and across the UK, interspersed with some temporary drier interludes. These will bring occasional spells of rain, which may be heavy at times bringing the risk of some impacts given how wet it has been lately. In addition, there may also be potential for some periods of strong winds at times too. Whilst it will often be mild, later in the period there may be a transition for temperatures to return closer to average, with a slightly higher chance of some wintry hazards across northern parts of the UK, especially on high ground.

Fri 12 Dec Wales

A continuation of a similar pattern to that seen through early December is anticipated, especially at first, as frontal systems from the Atlantic spread into and across the UK, interspersed with some temporary drier interludes. These will bring occasional spells of rain, which may be heavy at times bringing the risk of some impacts given how wet it has been lately. In addition, there may also be potential for some periods of strong winds at times too. Whilst it will often be mild, later in the period there may be a transition for temperatures to return closer to average, with a slightly higher chance of some wintry hazards across northern parts of the UK, especially on high ground.

Treharris Weather Forecast

Today 6 Dec Wales

Tonight 6 Dec Wales

Sun 7 Dec Wales

Mon 8 Dec Wales

Tue 9 Dec Wales

Wed 10 Dec Wales

Thu 11 Dec Wales

Fri 12 Dec Wales

Temperature Forecast Met Office

Temperature Real-Time

Cobbacombe Cross (Devon) Radar

National Satellite

National Synoptic

Treharris Temperature Statistics

December Temperature

St-athan (30km)

Lowest 9 January, 2025

Average 2025

Highest 12 August, 2025

Lowest 21 November, 2025

Average November

Highest 5 November, 2025

Lowest 5 December, 2025

Average December

Highest 1 December, 2025

Climate (2020–Present)

St-athan (30km)

Average Low 2020–2025

Average 2020–2025

Average High 2020–2025