Mariehamn Temperature by Month

Mariehamn in Åland Islands, Finland sees significant seasonal temperature differences, with daytime highs between 1°C (34°F) in February and 20°C (68°F) in August, averaging 10°C (50°F) annually. Explore the full monthly breakdown below.

In Mariehamn, temperatures can shift dramatically between pleasant in summer and very cold in winter. Nights follow the same pattern, with lows ranging from 15°C (59°F) in August to -3°C (27°F) in February.

The chart below illustrates the average maximum day and minimum night temperatures in Mariehamn by month:

Daily lows are most common between 4 AM and 6 AM. By 3 PM temperatures reach their daily high, driven by peak solar heating.

The chart below shows the average temperature throughout the year:

Mariehamn's average annual maximum temperature is 10°C (50°F). To put that in context, here's how it compares to a few well-known destinations:

Athens, Greece sits at 23°C (73°F) on average, with hot dry summers and mild winters characteristic of the Mediterranean.

Reykjavík, Iceland averages 9°C (48°F) a year, mild summers by Icelandic standards, but cold winters and frequent wind.

Chicago, USA averages 15°C (59°F) annually, known for extreme seasonal swings, from bitterly cold winters to warm summers.

Tokyo, Japan averages 21°C (70°F) a year, with hot summers, cool winters, and a well-defined cherry blossom spring.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Global average temperatures have risen by around 1.2°C since the pre-industrial era, and the effects are visible across many regions. Winters are milder on average, with fewer frost days and less snow in many parts of the world. Heatwaves are more frequent and more intense, and Europe's summers of 2018, 2019, and 2020 all set records.

Summers are also getting drier in some areas, while winter rainfall has increased in others. This contributies to higher river levels and more flooding. In many countries, spring arrives earlier and autumn lasts longer. It has knock-on effects for wildlife, agriculture, and local ecosystems.

For more on Mariehamn's weather, including monthly rainfall, sunshine hours, and humidity, visit our Mariehamn climate page.