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Weather & Climate in Carmarthen, United Kingdom
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Carmarthen experiences four distinct seasons with an average annual temperature of 49°F (10°C). Winters average 41°F in January while summers reach 60°F in July / relatively mild seasonal variation. The area gets 245 sunny days per year, above the national average. Annual precipitation totals 50.0 inches (wetter than the 38-inch national average). The city sits at an elevation of 75 feet.
Temperature
41°F Jan (5°C)
60°F Jul (16°C)
| Annual Average | 49.4°F |
| 9% below US avg | |
| January Average | 41°F (5°C) |
| July Average | 60°F (16°C) |
| Sunny Days | 245 days/yr |
Geography
| Elevation | 75 ft (23 m) |
| Area | 806.1 sq mi (2,087.7 km²) |
| Population Density | 1,967/sq mi |
| Coordinates | 51.8555°N, 4.3054°W |
| Timezone | Europe/London |
Precipitation & Snow
Air Quality
Earthquake History
33 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.7.
| Apr 2, 1990 | 4 km NNE of Presteigne, United Kingdom | M4.7 | 104 km | 18 km |
| Oct 25, 1999 | 10 km N of Hirwaun, United Kingdom | M4.5 | 53 km | 10 km |
| Feb 17, 2018 | 5 km NE of Clydach, United Kingdom | M4.3 | 34 km | 12 km |
| Feb 20, 2014 | 17 km NNW of Ilfracombe, United Kingdom | M4.1 | 56 km | 3 km |
| May 31, 2001 | 20 km NNW of Flexbury, United Kingdom | M4.0 | 99 km | 29 km |
| Mar 7, 1996 | 3 km SW of Clive, United Kingdom | M3.8 | 147 km | 10 km |
| May 29, 2013 | 14 km WSW of Nefyn, United Kingdom | M3.8 | 118 km | 10 km |
| Jan 29, 2004 | 2 km E of North Petherton, United Kingdom | M3.7 | 125 km | 7 km |
| Jan 1, 1994 | Wales-England region, United Kingdom | M3.6 | 88 km | 10 km |
| Jan 29, 2004 | 2 km E of North Petherton, United Kingdom | M3.6 | 125 km | 7 km |
| Jul 29, 1992 | 8 km WNW of Caernarfon, United Kingdom | M3.5 | 145 km | 10 km |
| Mar 17, 1994 | 5 km WNW of Newtown, United Kingdom | M3.5 | 99 km | 10 km |
| Feb 12, 2002 | 1 km SSE of Deri, United Kingdom | M3.5 | 74 km | 8 km |
| Oct 10, 2001 | 2 km SSE of Caerphilly, United Kingdom | M3.5 | 83 km | 10 km |
| Jun 20, 2002 | 3 km N of Marshfield, United Kingdom | M3.4 | 90 km | 14 km |
| Feb 24, 2023 | 1 km ENE of Brynmawr, United Kingdom | M3.4 | 79 km | 10 km |
| Jan 29, 2004 | 2 km E of North Petherton, United Kingdom | M3.3 | 125 km | 7 km |
| Sep 23, 1992 | 1 km NNE of Tiverton, United Kingdom | M3.3 | 119 km | 10 km |
| Jun 16, 1991 | 11 km WSW of Knighton, United Kingdom | M3.3 | 90 km | 10 km |
| Jul 30, 1999 | 2 km ENE of Bargoed, United Kingdom | M3.3 | 78 km | 6 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 41°F (5°C) | 5.2 in | |
| February | 40°F (5°C) | 3.7 in | Coldest |
| March | 43°F (6°C) | 4.1 in | |
| April | 46°F (8°C) | 3.0 in | |
| May | 51°F (11°C) | 2.9 in | Driest |
| June | 56°F (13°C) | 3.2 in | |
| July | 60°F (16°C) | 3.2 in | Warmest |
| August | 60°F (16°C) | 3.9 in | |
| September | 56°F (13°C) | 4.3 in | |
| October | 51°F (11°C) | 5.3 in | |
| November | 46°F (8°C) | 5.7 in | Wettest |
| December | 43°F (6°C) | 5.5 in |
Carmarthen has a seasonal temperature swing of 20°F / from 40°F in February to 60°F in July. Total annual precipitation is 50.0 inches, with November being the wettest month (5.7") and May the driest (2.9").