Aland Islands weather by month
Average temperatures and rainfall across Aland Islands, based on 30 years of climate data.
The average temperature in Aland Islands is around 7° across the year, though it swings month to month and from region to region. The figures below show the monthly pattern for Mariehamn.
- Hottest
- Aug
- 18°
- Coldest
- Feb
- -2°
- Wettest
- Oct
- 62 mm
- Driest
- Mar
- 27 mm
- Annual avg
- 7°
- year-round
- Rain / yr
- 545 mm
- 111 wet days
- Largest city
- Mariehamn
- 11k people
- Cities
- 1
- with climate data
Monthly climate (Mariehamn)
Average highs, lows and rainfall through the year for Mariehamn, Aland Islands's largest city.
| Month | High / Low | Rainfall | Wet days |
|---|---|---|---|
| Jan | 2° / -1° | 43 mm | 10.5 |
| Feb | 0° / -2° | 29 mm | 7.7 |
| Mar | 1° / -1° | 27 mm | 7.1 |
| Apr | 4° / 2° | 29 mm | 6.9 |
| May | 8° / 6° | 33 mm | 6.6 |
| Jun | 13° / 11° | 49 mm | 7.5 |
| Jul | 17° / 15° | 48 mm | 7.6 |
| Aug | 18° / 16° | 55 mm | 10.2 |
| Sep | 14° / 13° | 54 mm | 9.2 |
| Oct | 9° / 8° | 62 mm | 11.8 |
| Nov | 6° / 4° | 60 mm | 13 |
| Dec | 3° / 1° | 56 mm | 13 |
Climate in Mariehamn
Full Mariehamn forecastMariehamn is the largest city in Aland Islands; its cloud cover, humidity, wind and sunshine are typical of the surrounding region.
Clouds and sunshine
How often the daytime sky is clear, partly cloudy or overcast through the year.
In Mariehamn, the average share of the sky covered by clouds shows significant seasonal variation over the course of the year.
The clearer part of the year begins around March 18 and lasts for 6.6 months, ending around October 3. The clearest month is July, when the sky is clear, mostly clear, or partly cloudy 62% of the time on average.
The cloudier part of the year begins around October 4 and lasts for 5.4 months, ending around March 17. The cloudiest month is November, when it is overcast or mostly cloudy 78% of the time.
Humidity comfort
Share of days at each humidity comfort level, based on the dew point — the measure that tracks how muggy it actually feels.
Wind
Average wind speed through the year, banded into plain-language speed zones so a number reads as 'breezy' or 'calm' without knowing the scale.
This is the average sustained wind speed at the standard 10 metres above open ground — the steady flow a weather station reports, not the sharper gusts that come and go, which can run half again as fast. It's the number that says whether a place is generally breezy or calm.
Across the year, average wind speed in Mariehamn is typically breezy, near 25 km/h, and varies a lot with the seasons.
The windier part of the year lasts 5.8 months, from around Sep 20 to Mar 15. The windiest month is December, averaging about 30 km/h (windy).
The calmer part of the year runs from around Mar 16 to Sep 19, with July the calmest month at about 20 km/h.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (km/h) | 29 | 27 | 25 | 22 | 20 | 20 | 20 | 22 | 24 | 27 | 29 | 30 |
| Feels | windy | breezy | breezy | breezy | breezy | breezy | light breeze | breezy | breezy | breezy | breezy | windy |
| Wind speed (km/h) | Feels | |
|---|---|---|
| Jan | 29 | windy |
| Feb | 27 | breezy |
| Mar | 25 | breezy |
| Apr | 22 | breezy |
| May | 20 | breezy |
| Jun | 20 | breezy |
| Jul | 20 | light breeze |
| Aug | 22 | breezy |
| Sep | 24 | breezy |
| Oct | 27 | breezy |
| Nov | 29 | breezy |
| Dec | 30 | windy |
Best time to visit Aland Islands
A 0–10 score combining daytime comfort, chance of rain and cloud cover — the sweet spot runs early July to late August.
Solar energy
Average daily shortwave solar energy reaching the ground, banded into brightness zones so the number means something at a glance.
Solar energy is how much sunlight actually reaches the ground each day, measured in kilowatt-hours per square metre (kWh/m²) — the combined effect of how long the sun is up, how high it climbs, and how much cloud gets in the way. It's the raw fuel a solar panel has to work with: for scale, 1 kWh/m² a day is dim and wintry, while 7+ is desert-bright.
Mariehamn receives about 2.9 kWh/m² a day of solar energy on average — moderate — with a clear seasonal swing between 0.2 and 6.3 kWh/m².
The brighter stretch of the year lasts 5.6 months, from around Mar 26 to Sep 12. The brightest month is June, averaging about 6.3 kWh/m² (intense).
The dimmest month is December, down near 0.2 kWh/m² — roughly 97% less than the June peak.
Where is Aland Islands?
Aland Islands sits around 60.1°N, 19.9°E. The marker shows Mariehamn, its largest city, among 1 city with climate data here.
