Jersey (St Helier) climate
Jersey (St Helier) (Jersey, a British Crown Dependency) has a temperate oceanic climate (Köppen Cfb). The average temperature over the year is 12 °C54 °F, and about 772 mm30 in of precipitation falls in an average year.
Temperature by month
Precipitation by month
Jersey (St Helier) climate table
| Month | High °C°F | Low °C°F | Mean °C°F | Precip. mmin |
|---|---|---|---|---|
| Jan | 948 | 643 | 745 | 803.2 |
| Feb | 947 | 542 | 745 | 672.6 |
| Mar | 1050 | 643 | 847 | 592.3 |
| Apr | 1254 | 847 | 1051 | 431.7 |
| May | 1559 | 1151 | 1355 | 532.1 |
| Jun | 1864 | 1456 | 1660 | 471.9 |
| Jul | 1967 | 1560 | 1763 | 512.0 |
| Aug | 2068 | 1661 | 1864 | 542.1 |
| Sep | 1965 | 1559 | 1762 | 471.8 |
| Oct | 1661 | 1355 | 1458 | 823.2 |
| Nov | 1254 | 1049 | 1152 | 953.7 |
| Dec | 1050 | 745 | 847 | 943.7 |
| Year | 2068 | 542 | 1254 | 77230 |
“Year” row: highest monthly high, lowest monthly low, annual mean and annual total.
| Month | Humid. | Cloud | Solar | Daylight |
|---|---|---|---|---|
| Jan | 87% | 85% | 0.9 | 8:38 |
| Feb | 85% | 82% | 1.6 | 10:04 |
| Mar | 85% | 77% | 2.9 | 11:44 |
| Apr | 82% | 68% | 4.7 | 13:39 |
| May | 83% | 68% | 5.7 | 15:17 |
| Jun | 83% | 66% | 6.0 | 16:12 |
| Jul | 82% | 63% | 5.9 | 15:50 |
| Aug | 82% | 67% | 4.9 | 14:23 |
| Sep | 81% | 67% | 3.7 | 12:31 |
| Oct | 83% | 78% | 2.1 | 10:40 |
| Nov | 85% | 85% | 1.1 | 9:02 |
| Dec | 86% | 86% | 0.7 | 8:13 |
Humid. = average relative humidity at 2 m; cloud = average cloud amount; solar = average daily solar energy reaching the ground in kWh/m² (all-sky); daylight in hours:minutes, calculated for the 15th of each month.
What the climate of Jersey (St Helier) is like
The warmest month is August, with an average high of 20 °C68 °F and a low of 16 °C61 °F. The coldest is February, when highs average 9 °C47 °F and lows 5 °C42 °F. There is a clear seasonal cycle, with 10.9 °C19.6 °F between the average temperature of the warmest and the coolest month.
Annual precipitation is moderate at about 772 mm30 in. The wettest three-month stretch is October–December, which brings 35% of the annual total. The wettest month is November (95 mm3.7 in), the driest is April (43 mm1.7 in).
Relative humidity ranges from 81% in September to 87% in January. The clearest skies (lowest average cloud amount, 63%) are typical of July. Average wind speed near the ground ranges from 15 km/h (9 mph) in June to 22 km/h (14 mph) in January. Daylight lasts from about 8.2 hours in December to 16.2 hours in June.
Best time to visit Jersey (St Helier)
Based on these averages, the most comfortable months for sightseeing and outdoor activities are July–September: average highs of 19 °C65 °F to 20 °C68 °F with 47 mm1.8 in to 54 mm2.1 in of precipitation per month.
The most challenging month is December, which is cold, with average highs of 10 °C50 °F.
Comfort score: months are ranked by how close they come to an average high of 21–28 °C (70–82 °F), lows above 5 °C (41 °F), little precipitation and moderate humidity. The best-ranked months of each place are recommended, even where none meets all of these. These are general rules of thumb applied to long-term averages.
What to pack for Jersey (St Helier)
- Winter (December–February) — highs 947 to 10 °C50 °F, lows 542 to 7 °C45 °F, about 80 mm3.2 in of precipitation a month. Pack a warm coat, layers and closed shoes.
- Spring (March–May) — highs 1050 to 15 °C59 °F, lows 643 to 11 °C51 °F, about 52 mm2.0 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket.
- Summer (June–August) — highs 1864 to 20 °C68 °F, lows 1456 to 16 °C61 °F, about 51 mm2.0 in of precipitation a month. Pack light layers — T-shirts plus a light sweater or jacket.
- Autumn (September–November) — highs 1254 to 19 °C65 °F, lows 1049 to 15 °C59 °F, about 75 mm2.9 in of precipitation a month. Pack long sleeves, a sweater and a medium jacket.
How Jersey (St Helier) compares
Compared with Rennes, about 124 km to the south, Jersey (St Helier) is on average 0.5 °C0.8 °F warmer and receives 9% more precipitation (772 mm30 in vs 708 mm28 in). The difference is largest in December (2.6 °C4.6 °F warmer).
Of the 66 places in the United Kingdom covered by World Climates, Jersey (St Helier) is the 3rd warmest by annual mean temperature and the 38th wettest by annual precipitation. See all of them on the United Kingdom climate page.
Places in other countries with the most similar temperature and rainfall pattern (seasons shifted for the other hemisphere where needed): Le Havre (France, Cfb), Brest (France, Cfb) and Christchurch (New Zealand, Cfb).
Nearby places
- Guernsey (St Peter Port) 43 km · 12 °C54 °F · 847 mm33 in
- Rennes 124 km · 12 °C53 °F · 708 mm28 in
- Caen 127 km · 12 °C53 °F · 745 mm29 in
- Le Havre 164 km · 12 °C53 °F · 803 mm32 in
- Bournemouth 171 km · 12 °C53 °F · 845 mm33 in
- Brest 196 km · 12 °C54 °F · 897 mm35 in
- Plymouth 197 km · 11 °C53 °F · 1,164 mm46 in
- Southampton 197 km · 11 °C52 °F · 779 mm31 in
Frequently asked questions
What is the warmest month in Jersey (St Helier)?
August is the warmest month in Jersey (St Helier), with an average high of 20 °C (68 °F) and an average low of 16 °C (61 °F).
What is the coldest month in Jersey (St Helier)?
February is the coldest month, with an average high of 9 °C (47 °F) and an average low of 5 °C (42 °F).
When does it rain the most in Jersey (St Helier)?
November is the wettest month with about 95 mm (3.7 in) of precipitation; April is the driest with about 43 mm (1.7 in).
What is the best time to visit Jersey (St Helier)?
Judging by long-term averages, the most comfortable months are July–September.
About this data
All figures are 25-year averages (January 2001 – December 2025) from the NASA POWER project. Temperature, humidity, wind and precipitation come from the MERRA-2 reanalysis (precipitation is the bias-corrected MERRA-2 product), cloud and solar values from CERES satellite data. They describe a grid cell of roughly 50–70 km, not a single weather station, so they can differ from airport records — most of all on coasts, in mountains and for rainfall. Average highs and lows are the monthly mean temperature plus/minus half of the average daily temperature range. Counts of rainy days are not part of this dataset.