Weather in Mariehamn in August 2025
Average weather
Average temperature in Mariehamn in August
Going from a maximum of +22°C during the day to a minimum of +13°C during the night, the temperature in August averages around +18°C.
The average maximum temperature goes down 11% by the end of the month, compared with the beginning of the month, from +18°C to +17°C.
Is Mariehamn warm or cold in August?
Mariehamn is typically mild in August.
Maximum temperatures go down compared to the previous month from +19°C to +18°C. The minimum temperature also goes up from +14°C to +14°C.
Pack a light jacket as it will be warm in the day and cool in the evenings.
August is one of the warmest months in Mariehamn, here is the comparison with other months:
Climate in Mariehamn in August
| July | August | September | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +19°C | +18°C | +14°C | ||||
| Min. temperature | ||||||
| +6°C | +6°C | +1°C | ||||
| Max. temperature | ||||||
| +30°C | +28°C | +24°C | ||||
| Rainfall | ||||||
| 49 mm | 63 mm | 55 mm | ||||
| Wind | ||||||
| 4 m/s | 5 m/s | 6 m/s | ||||
| Humidity | ||||||
| 84% | 83% | 81% | ||||
| Air pressure | ||||||
| 1010 HPa | 1011 HPa | 1012 HPa | ||||
| Sunny days | ||||||
| 9 | 7 | 4 | ||||
| Cloudy days | ||||||
| 9 | 8 | 10 | ||||
| Rainy days | ||||||
| 12 | 16 | 15 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
August typically has worse weather conditions compared to July. It’s getting colder in August. From +19°C in the day, the average maximum temperature lowers to +18°C. Prepare for more rain. Average rainfall goes from 49 mm to 63 mm. It feels drier, as humidity decreases from 84% to 83%. Winds are stronger in comparison to July, going up from 4 m/s to 5 m/s on average. The days becoming less sunny, going from 9 sunny days in July to 7 in August.
September brings much the same weather, it remains ok.
Wind
The average wind speed is 4 m/s getting up to 8 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Mariehamn is gradually decreasing during August, going from 4 m/s to 3 m/s over the course of the month.
Rain
How was the weather last August in Mariehamn?
Climate Change over Years
The climate in Mariehamn in August has not changed much over the last 43 years.
The average temperature was the lowest in 1987 (+5°C) and the highest in 2020 (+11°C). The driest year was 2018 with only 269 mm of rainfall, and the wettest year was 2020 with 612 mm.
FAQ
Is August a good time to visit Mariehamn?
Can you sunbathe in Mariehamn in August?
Is Mariehamn rainy in August?
Is it sunny in Mariehamn in August?
Monthly weather in Mariehamn
Source of the data
For this page, we’ve looked at the typical weather in Mariehamn, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.