Mariehamn weather by month & the best time to visit
Finland · seaside town · oceanic / maritime climate
The best time to visit Mariehamn is July — its sunniest month (Sunshine Score 66/100), with August close behind. Mariehamn averages about 1,841 hours of sunshine a year. Daytime highs around 18°C / 64°F and roughly 58 mm of rain in July.
When is the best time to visit Mariehamn?
For sunshine, the best time to visit Mariehamn is July, then August. The dullest month is January (0/100, 53 mm of rain). The full month-by-month picture is in the table below.
How sunny is Mariehamn?
Mariehamn gets a moderate 1,841 hours of sunshine a year. 66 Sunshine Score points separate July (66) from January (0), so the month you pick matters. It ranks #3 of 20 destinations in Finland for annual sunshine, above the national median of 1,638 hours. The year's 649 mm of rain spreads fairly evenly across the months, with no pronounced dry season.
Sunshine Score by month
| Month | Score | Day high | Night low | Rain | UV | Sea |
|---|---|---|---|---|---|---|
| January | 0 | 1° / 34°F | -1° / 30°F | 53 mm | 0 | 0° / 32°F |
| February | 0 | 0° / 32°F | -2° / 28°F | 40 mm | 0 | 0° / 32°F |
| March | 0 | 1° / 34°F | -1° / 30°F | 38 mm | 1 | 1° / 34°F |
| April | 0 | 5° / 41°F | 2° / 36°F | 36 mm | 2 | 3° / 37°F |
| May | 14 | 10° / 50°F | 6° / 43°F | 42 mm | 3 | 9° / 48°F |
| June | 39 | 14° / 57°F | 11° / 52°F | 58 mm | 4 | 16° / 61°F |
| July | 66 | 18° / 64°F | 16° / 61°F | 58 mm | 4 | 18° / 64°F |
| August | 65 | 18° / 64°F | 16° / 61°F | 64 mm | 3 | 19° / 66°F |
| September | 46 | 15° / 59°F | 12° / 54°F | 60 mm | 2 | 16° / 61°F |
| October | 6 | 9° / 48°F | 7° / 45°F | 70 mm | 1 | 11° / 52°F |
| November | 0 | 6° / 43°F | 4° / 39°F | 68 mm | 0 | 6° / 43°F |
| December | 0 | 3° / 37°F | 1° / 34°F | 62 mm | 0 | 3° / 37°F |
Sea temperature in Mariehamn by month
The sea off Mariehamn is warmest in August at around 19°C / 66°F, and coolest in January at 0°C / 32°F. It never reaches comfortable swimming temperatures (21°C+). Month-by-month sea-surface temperatures are in the Sea column of the table above.
Nearest destinations
Mariehamn: questions and answers
What kind of destination is Mariehamn?
Mariehamn is a seaside town in Finland with a oceanic / maritime climate — the sea reaches 19°C at its warmest.
How many hours of sunshine does Mariehamn get a year?
Mariehamn gets about 1,841 hours of sunshine a year, at its best around July.
When is the best time to visit Mariehamn?
The sunniest time to visit Mariehamn is July, when the Sunshine Score peaks at 66/100 (with August close behind). Expect daytime highs around 18°C / 64°F.
What is the least sunny month in Mariehamn?
January is the least sunny month in Mariehamn, scoring 0/100 with about 53 mm of rain.
What is the sea temperature in Mariehamn?
The sea in Mariehamn ranges from about 0°C (January) to 19°C (August). Month-by-month sea temperatures are on this page.
How strong is the sun in Mariehamn?
The typical midday UV index in Mariehamn peaks around 4 (moderate) in June, easing to about 0 (low) in January. Month-by-month midday UV values are in the UV column of the table on this page.
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