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Mariehamn, Åland Islands climate
Cfb Oceanic / temperate
Mariehamn has a seasonal cold-temperate climate (Oceanic / temperate, Köppen Cfb). The hottest month is July with an average daily high near 21°C, while the coldest is February averaging around −5°C at night. Around 565 mm of precipitation falls each year, peaking in August (79 mm) and easing off in May (27 mm). At latitude 60°N, day length swings from 5.5 hours in midwinter to 18.5 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)Mariehamn climate normals (1991–2020)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°C) | 1 | 0 | 3 | 8 | 14 | 17 | 21 | 20 | 15 | 10 | 5 | 3 |
| Avg temp (°C) | −2 | −2 | 0 | 4 | 9 | 13 | 17 | 16 | 12 | 7 | 3 | 0 |
| Avg low (°C) | −4 | −5 | −3 | 0 | 4 | 9 | 12 | 12 | 8 | 4 | 1 | −2 |
| Precipitation (mm) | 38 | 28 | 42 | 31 | 27 | 57 | 49 | 79 | 55 | 73 | 42 | 44 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Avg high (°C) | 1 | 0 | 3 | 8 | 14 | 17 |
| Avg temp (°C) | −2 | −2 | 0 | 4 | 9 | 13 |
| Avg low (°C) | −4 | −5 | −3 | 0 | 4 | 9 |
| Precipitation (mm) | 38 | 28 | 42 | 31 | 27 | 57 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Avg high (°C) | 21 | 20 | 15 | 10 | 5 | 3 |
| Avg temp (°C) | 17 | 16 | 12 | 7 | 3 | 0 |
| Avg low (°C) | 12 | 12 | 8 | 4 | 1 | −2 |
| Precipitation (mm) | 49 | 79 | 55 | 73 | 42 | 44 |
How often — frequency of weather events
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 3 | 2 | 3 | 2 | 1 | 2 | 1 | 2 | 2 | 2 | 2 | 2 |
| Days with low ≤ 0°C (days) | 21 | 21 | 21 | 13 | 4 | 0.1 | — | — | 1 | 7 | 11 | 16 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 3 | 2 | 3 | 2 | 1 | 2 |
| Days with low ≤ 0°C (days) | 21 | 21 | 21 | 13 | 4 | 0.1 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Days with measurable rain (days) | 1 | 2 | 2 | 2 | 2 | 2 |
| Days with low ≤ 0°C (days) | — | — | 1 | 7 | 11 | 16 |
Sky & atmosphere
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cloud cover (%) | 81 | 77 | 69 | 63 | 59 | 60 | 60 | 60 | 63 | 75 | 82 | 80 |
| Relative humidity (%) | 87 | 89 | 87 | 86 | 84 | 83 | 82 | 81 | 83 | 85 | 87 | 88 |
| Wind speed (m/s) | 6.6 | 5.9 | 5.5 | 4.9 | 4.3 | 4.3 | 4.4 | 4.8 | 5.6 | 6.1 | 6.4 | 6.6 |
| Jan – Jun | Jan | Feb | Mar | Apr | May | Jun |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 81 | 77 | 69 | 63 | 59 | 60 |
| Relative humidity (%) | 87 | 89 | 87 | 86 | 84 | 83 |
| Wind speed (m/s) | 6.6 | 5.9 | 5.5 | 4.9 | 4.3 | 4.3 |
| Jul – Dec | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|
| Cloud cover (%) | 60 | 60 | 63 | 75 | 82 | 80 |
| Relative humidity (%) | 82 | 81 | 83 | 85 | 87 | 88 |
| Wind speed (m/s) | 4.4 | 4.8 | 5.6 | 6.1 | 6.4 | 6.6 |
Methodology & sources
Temperature & precipitation — 1991–2020 normals computed from 25 years of daily observations at Jomala Maarianhaminan Lentoase, a weather station, about 3 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.