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Boulogne-sur-Mer, Hauts-de-France climate
Cfb Oceanic / temperate
Boulogne-sur-Mer has a mildly seasonal cool-temperate climate (Oceanic / temperate, Köppen Cfb). The hottest month is August with an average daily high near 70°F, while the coldest is January averaging around 38°F at night. Around 26 inches of precipitation falls each year, peaking in November (3.5 inches) and easing off in April (1.5 inches). At latitude 51°N, day length swings from 7.7 hours in midwinter to 16.2 hours at midsummer.
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)Boulogne-sur-Mer climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 45 | 45 | 50 | 55 | 61 | 65 | 69 | 70 | 65 | 59 | 52 | 47 |
| Avg temp (°F) | 41 | 42 | 45 | 50 | 55 | 60 | 64 | 64 | 61 | 55 | 48 | 43 |
| Avg low (°F) | 38 | 38 | 41 | 44 | 49 | 54 | 58 | 59 | 56 | 50 | 44 | 39 |
| Precipitation (in) | 2.4 | 1.7 | 1.5 | 1.5 | 1.8 | 1.6 | 1.9 | 2.1 | 2.2 | 3.0 | 3.5 | 3.3 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°F) | 45 | 45 | 50 | 55 | 61 | 65 |
| Avg temp (°F) | 41 | 42 | 45 | 50 | 55 | 60 |
| Avg low (°F) | 38 | 38 | 41 | 44 | 49 | 54 |
| Precipitation (in) | 2.4 | 1.7 | 1.5 | 1.5 | 1.8 | 1.6 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°F) | 69 | 70 | 65 | 59 | 52 | 47 |
| Avg temp (°F) | 64 | 64 | 61 | 55 | 48 | 43 |
| Avg low (°F) | 58 | 59 | 56 | 50 | 44 | 39 |
| Precipitation (in) | 1.9 | 2.1 | 2.2 | 3.0 | 3.5 | 3.3 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 76 | 75 | 72 | 66 | 66 | 66 | 63 | 65 | 66 | 72 | 78 | 77 |
| Relative humidity (%) | 92 | 90 | 87 | 83 | 82 | 82 | 82 | 83 | 84 | 87 | 91 | 93 |
| Wind speed (mph) | 9.7 | 9.2 | 8.6 | 7.4 | 7.2 | 6.8 | 6.7 | 6.6 | 7.0 | 8.1 | 8.5 | 9.1 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 76 | 75 | 72 | 66 | 66 | 66 |
| Relative humidity (%) | 92 | 90 | 87 | 83 | 82 | 82 |
| Wind speed (mph) | 9.7 | 9.2 | 8.6 | 7.4 | 7.2 | 6.8 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 63 | 65 | 66 | 72 | 78 | 77 |
| Relative humidity (%) | 82 | 83 | 84 | 87 | 91 | 93 |
| Wind speed (mph) | 6.7 | 6.6 | 7.0 | 8.1 | 8.5 | 9.1 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 30 years of daily observations at Boulogne, a weather station, about 1 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.