Climate averages 1991–2020
Mariehamn weather
in December.
A cold, moderately wet month: the 9th warmest and the 10th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
December is a cold month in Mariehamn: daytime highs average 2.8°C and nights cool to about 0.4°C. By daytime temperature it is the 9th warmest of the 12 months.
Expect about 56 mm of rain on roughly 13 days, which makes December a moderately wet month (the 10th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 6 h 01 min on an average December day.
The nearest other city in this atlas is Uppsala (130 km away). In December its highs average 0.9°C, 1.9°C cooler than Mariehamn, with 41 mm of precipitation.
From December to January, average highs fall by 1.8°C to 1.0°C, and monthly precipitation falls from 56 mm to 43 mm.
The annual picture
December in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Mariehamn climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 1.0°C-1.6°C | -1.6°C | 43 | 10.5 | 6.87 h |
| February | -0.2°C-2.9°C | -2.9°C | 29 | 7.8 | 9.19 h |
| March | 1.5°C-1.5°C | -1.5°C | 27 | 7.1 | 11.712 h |
| April | 5.2°C1.8°C | 1.8°C | 29 | 6.9 | 14.515 h |
| May | 9.7°C6.1°C | 6.1°C | 33 | 6.6 | 17.117 h |
| June | 14.5°C10.9°C | 10.9°C | 49 | 7.5 | 18.719 h |
| July | 18.4°C15.1°C | 15.1°C | 48 | 7.6 | 18.018 h |
| August | 18.3°C15.4°C | 15.4°C | 55 | 10.2 | 15.716 h |
| September | 14.3°C11.8°C | 11.8°C | 54 | 9.2 | 13.013 h |
| October | 9.1°C7.0°C | 7.0°C | 62 | 11.8 | 10.210 h |
| November | 5.3°C3.2°C | 3.2°C | 60 | 13.0 | 7.68 h |
| December, selected | 2.8°C0.4°C | 0.4°C | 56 | 13.0 | 6.06 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
December in nearby cities
- Uppsala in DecemberSweden · 130 kmHigh 0.9°C · Low -3.1°C · 41 mm precipitation
- Sollentuna in DecemberSweden · 134 kmHigh 1.3°C · Low -2.2°C · 43 mm precipitation
- Turku in DecemberFinland · 135 kmHigh 0.4°C · Low -3.5°C · 56 mm precipitation
- Stockholm in DecemberSweden · 135 kmHigh 1.7°C · Low -1.6°C · 45 mm precipitation
- Haninge in DecemberSweden · 144 kmHigh 1.7°C · Low -1.5°C · 51 mm precipitation
- Huddinge in DecemberSweden · 146 kmHigh 1.7°C · Low -1.6°C · 45 mm precipitation
- Södertälje in DecemberSweden · 164 kmHigh 1.3°C · Low -2.4°C · 44 mm precipitation
- Gävle in DecemberSweden · 166 kmHigh 0.6°C · Low -3.3°C · 42 mm precipitation
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Mariehamn) is explained once on the Mariehamn year overview and on the Sources, method and limits page.