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Saint Helier, Jersey climate
Cfb Oceanic / temperate
Saint Helier has a mildly seasonal cool-temperate climate (Oceanic / temperate, Köppen Cfb). The hottest month is August with an average daily high near 69°F, while the coldest is February averaging around 40°F at night. Around 35 inches of precipitation falls each year, peaking in December (4.8 inches) and easing off in July (1.8 inches).
Temperature & precipitation
Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figuresHours of sunshine per day
Estimated sunny hours each month — daylight length × clear-sky fraction · 1991–2020 monthly cloud cover (NASA POWER)Saint Helier climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 48 | 48 | 52 | 56 | 61 | 66 | 69 | 69 | 66 | 60 | 54 | 50 |
| Avg temp (°F) | 44 | 44 | 47 | 50 | 55 | 60 | 63 | 64 | 61 | 56 | 50 | 46 |
| Avg low (°F) | 40 | 40 | 42 | 44 | 49 | 54 | 57 | 58 | 56 | 51 | 46 | 42 |
| Precipitation (in) | 3.7 | 3.0 | 2.5 | 2.2 | 2.0 | 2.0 | 1.8 | 2.3 | 2.4 | 4.0 | 4.4 | 4.8 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 48 | 48 | 52 | 56 | 61 | 66 |
| Avg temp (°F) | 44 | 44 | 47 | 50 | 55 | 60 |
| Avg low (°F) | 40 | 40 | 42 | 44 | 49 | 54 |
| Precipitation (in) | 3.7 | 3.0 | 2.5 | 2.2 | 2.0 | 2.0 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 69 | 69 | 66 | 60 | 54 | 50 |
| Avg temp (°F) | 63 | 64 | 61 | 56 | 50 | 46 |
| Avg low (°F) | 57 | 58 | 56 | 51 | 46 | 42 |
| Precipitation (in) | 1.8 | 2.3 | 2.4 | 4.0 | 4.4 | 4.8 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 20 | 17 | 15 | 14 | 12 | 11 | 11 | 12 | 12 | 18 | 20 | 20 |
| Days with high ≥ 90°F (days) | — | — | — | — | — | 0.0 | 0.1 | 0.1 | — | — | — | — |
| Days with low ≤ 32°F (days) | 3 | 3 | 0.8 | 0.0 | — | — | — | — | — | — | 0.4 | 2 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 20 | 17 | 15 | 14 | 12 | 11 |
| Days with high ≥ 90°F (days) | — | — | — | — | — | 0.0 |
| Days with low ≤ 32°F (days) | 3 | 3 | 0.8 | 0.0 | — | — |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 11 | 12 | 12 | 18 | 20 | 20 |
| Days with high ≥ 90°F (days) | 0.1 | 0.1 | — | — | — | — |
| Days with low ≤ 32°F (days) | — | — | — | — | 0.4 | 2 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 83 | 81 | 77 | 69 | 68 | 66 | 64 | 67 | 67 | 77 | 82 | 83 |
| Relative humidity (%) | 84 | 84 | 85 | 84 | 85 | 86 | 86 | 84 | 82 | 82 | 83 | 84 |
| Wind speed (mph) | 15.6 | 14.4 | 12.8 | 11.3 | 10.5 | 9.7 | 9.6 | 10.0 | 11.7 | 13.8 | 15.1 | 15.8 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 83 | 81 | 77 | 69 | 68 | 66 |
| Relative humidity (%) | 84 | 84 | 85 | 84 | 85 | 86 |
| Wind speed (mph) | 15.6 | 14.4 | 12.8 | 11.3 | 10.5 | 9.7 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 64 | 67 | 67 | 77 | 82 | 83 |
| Relative humidity (%) | 86 | 84 | 82 | 82 | 83 | 84 |
| Wind speed (mph) | 9.6 | 10.0 | 11.7 | 13.8 | 15.1 | 15.8 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 30 years of daily observations at Jersey: Airport, a weather station, about 8 km from the city centre. The underlying daily records come from NOAA's global station network.
Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.