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Weather & Climate in St. Helier, United Kingdom
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
St. Helier experiences four distinct seasons with an average annual temperature of 53°F (12°C). Winters average 41°F in January while summers reach 64°F in July. The area gets 234 sunny days per year, above the national average. Annual precipitation totals 31.7 inches. The area receives 3.0 inches of snow annually. The city sits at an elevation of 157 feet.
Temperature
41°F Jan (5°C)
64°F Jul (18°C)
| Annual Average | 53.1°F |
| 2% below US avg | |
| January Average | 41°F (5°C) |
| July Average | 64°F (18°C) |
| Sunny Days | 234 days/yr |
Geography
| Elevation | 157 ft (48 m) |
| Area | 18.0 sq mi (46.5 km²) |
| Population Density | 666/sq mi |
| Coordinates | 51.3822°N, 0.1834°W |
| Timezone | Europe/London |
Precipitation & Snow
Air Quality
Earthquake History
31 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M4.6.
| Apr 28, 2007 | 1 km WNW of Lympne, United Kingdom | M4.6 | 89 km | 10 km |
| Feb 15, 1994 | 7 km ESE of Thetford, United Kingdom | M4.4 | 131 km | 10 km |
| Sep 23, 2000 | 1 km WSW of Warwick, United Kingdom | M4.0 | 140 km | 13 km |
| Sep 15, 1994 | 38 km NE of Broadstairs, United Kingdom | M3.9 | 139 km | 10 km |
| Jul 14, 2011 | 62 km SSE of Ventnor, United Kingdom | M3.9 | 146 km | 10 km |
| Jan 27, 1998 | 27 km W of Le Touquet-Paris-Plage, France | M3.8 | 138 km | 2 km |
| May 12, 1994 | 4 km S of Shipston on Stour, United Kingdom | M3.7 | 122 km | 10 km |
| May 22, 2015 | 3 km SSE of Ramsgate, United Kingdom | M3.7 | 113 km | 12 km |
| Mar 3, 2009 | 1 km ENE of Hawkinge, United Kingdom | M3.5 | 99 km | 4 km |
| Feb 17, 1992 | 1 km W of Warboys, United Kingdom | M3.4 | 114 km | 10 km |
| Feb 27, 2019 | 3 km SE of Dorking, United Kingdom | M3.3 | 21 km | 10 km |
| Sep 9, 1995 | 0 km WNW of East Wittering, United Kingdom | M3.3 | 84 km | 10 km |
| Feb 13, 1997 | 26 km W of Le Touquet-Paris-Plage, France | M3.2 | 137 km | 5 km |
| May 4, 1990 | 0 km NE of Coquelles, France | M3.1 | 147 km | 10 km |
| May 19, 2019 | 7 km ESE of Swanage, United Kingdom | M3.0 | 148 km | 10 km |
| Aug 26, 2002 | 40 km NNW of Étretat, France | M3.0 | 149 km | 4 km |
| Nov 5, 1994 | 5 km N of Debenham, United Kingdom | M3.0 | 137 km | 5 km |
| Jul 16, 2005 | 3 km WSW of Southwater, United Kingdom | M2.9 | 44 km | 5 km |
| Jan 27, 2015 | 1 km ENE of Winchester, United Kingdom | M2.9 | 85 km | 3 km |
| Mar 18, 2001 | 8 km W of Marlborough, United Kingdom | M2.9 | 115 km | 10 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tsunami History
2 tsunamis recorded within 500 km. Highest wave on record: 6.0 m (20 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1858 | NORTH SEA | Unknown | 6.0 m | — | 131 km |
| 1911 | FOLKSTONE, ENGLAND | Meteorological | 0.9 m | — | 104 km |
Source: NOAA/NCEI Historical Tsunami Database.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 41°F (5°C) | 2.5 in | Wettest |
| February | 41°F (5°C) | 1.6 in | Coldest, Driest |
| March | 44°F (7°C) | 1.9 in | |
| April | 48°F (9°C) | 1.7 in | |
| May | 54°F (12°C) | 1.9 in | |
| June | 60°F (16°C) | 2.1 in | |
| July | 64°F (18°C) | 1.7 in | Warmest |
| August | 64°F (18°C) | 2.0 in | |
| September | 59°F (15°C) | 2.2 in | |
| October | 52°F (11°C) | 2.4 in | |
| November | 46°F (8°C) | 2.4 in | |
| December | 42°F (6°C) | 2.4 in |
St. Helier has a seasonal temperature swing of 23°F / from 41°F in February to 64°F in July. Total annual precipitation is 24.9 inches, with January being the wettest month (2.5") and February the driest (1.6").