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Weather & Climate in Merthyr Tydfil, United Kingdom
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Merthyr Tydfil experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 41°F in January while summers reach 60°F in July / relatively mild seasonal variation. The area gets 224 sunny days per year, above the national average. Annual precipitation totals 69.6 inches (wetter than the 38-inch national average). The area receives 6.0 inches of snow annually. The city sits at an elevation of 610 feet.
Temperature
41°F Jan (5°C)
60°F Jul (15°C)
| Annual Average | 51.8°F |
| 4% below US avg | |
| January Average | 41°F (5°C) |
| July Average | 60°F (15°C) |
| Sunny Days | 224 days/yr |
Geography
| Elevation | 610 ft (186 m) |
| Area | 65.7 sq mi (170.3 km²) |
| Population Density | 667/sq mi |
| Coordinates | 51.7479°N, 3.3778°W |
| Timezone | Europe/London |
Precipitation & Snow
Air Quality
Earthquake History
37 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.8.
| Sep 22, 2002 | 2 km ESE of Wombourn, United Kingdom | M4.8 | 120 km | 9 km |
| Apr 2, 1990 | 4 km NNE of Presteigne, United Kingdom | M4.7 | 68 km | 18 km |
| Oct 25, 1999 | 10 km N of Hirwaun, United Kingdom | M4.5 | 15 km | 10 km |
| Feb 17, 2018 | 5 km NE of Clydach, United Kingdom | M4.3 | 33 km | 12 km |
| Feb 20, 2014 | 17 km NNW of Ilfracombe, United Kingdom | M4.1 | 69 km | 3 km |
| May 31, 2001 | 20 km NNW of Flexbury, United Kingdom | M4.0 | 123 km | 29 km |
| Sep 23, 2000 | 1 km WSW of Warwick, United Kingdom | M4.0 | 135 km | 13 km |
| Mar 7, 1996 | 3 km SW of Clive, United Kingdom | M3.8 | 123 km | 10 km |
| May 12, 1994 | 4 km S of Shipston on Stour, United Kingdom | M3.7 | 124 km | 10 km |
| Jan 29, 2004 | 2 km E of North Petherton, United Kingdom | M3.7 | 78 km | 7 km |
| Jan 1, 1994 | Wales-England region, United Kingdom | M3.6 | 51 km | 10 km |
| May 30, 2022 | 2 km ESE of Prees, United Kingdom | M3.6 | 136 km | 10 km |
| Jan 29, 2004 | 2 km E of North Petherton, United Kingdom | M3.6 | 78 km | 7 km |
| Mar 17, 1994 | 5 km WNW of Newtown, United Kingdom | M3.5 | 88 km | 10 km |
| Feb 12, 2002 | 1 km SSE of Deri, United Kingdom | M3.5 | 10 km | 8 km |
| Oct 10, 2001 | 2 km SSE of Caerphilly, United Kingdom | M3.5 | 25 km | 10 km |
| Feb 24, 2023 | 1 km ENE of Brynmawr, United Kingdom | M3.4 | 16 km | 10 km |
| Jun 20, 2002 | 3 km N of Marshfield, United Kingdom | M3.4 | 29 km | 14 km |
| Sep 23, 1992 | 1 km NNE of Tiverton, United Kingdom | M3.3 | 93 km | 10 km |
| Jun 16, 1991 | 11 km WSW of Knighton, United Kingdom | M3.3 | 63 km | 10 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tsunami History
1 tsunami recorded within 500 km. Highest wave on record: 0.4 m (1 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 2011 | PLYMOUTH, ENGLAND | Avalanche | 0.4 m | — | 141 km |
Source: NOAA/NCEI Historical Tsunami Database.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 41°F (5°C) | 6.4 in | |
| February | 38°F (3°C) | 4.5 in | Coldest |
| March | 41°F (5°C) | 4.8 in | |
| April | 44°F (7°C) | 3.5 in | |
| May | 50°F (10°C) | 3.3 in | |
| June | 55°F (13°C) | 3.4 in | |
| July | 60°F (15°C) | 3.2 in | Warmest, Driest |
| August | 59°F (15°C) | 4.2 in | |
| September | 55°F (13°C) | 4.8 in | |
| October | 49°F (9°C) | 5.6 in | |
| November | 43°F (6°C) | 6.3 in | |
| December | 40°F (4°C) | 6.5 in | Wettest |
Merthyr Tydfil has a seasonal temperature swing of 22°F / from 38°F in February to 60°F in July. Total annual precipitation is 56.4 inches, with December being the wettest month (6.5") and July the driest (3.2").