Sea temperature in Finland
Live water temperatures and swimming conditions across 9 beaches on the Finland coast.
Best time to swim in Finland
The sea in Finland peaks in August, when the water averages around 17°C.
On average, 0 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
Outside peak season the water drops toward 6°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable.
The coldest month is typically February at around 3°C, when cold-water swimmers dominate the coast.
Finland sea temperature history
Long-term climatology for Finland shows an annual mean sea temperature of 9°C, ranging from 3°C in winter to 17°C at the summer peak.
The seasonal swing is roughly 14°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at Finland, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Values are area averages; individual beaches vary by exposure and depth.
Finland sea temperature: frequently asked questions
What is the warmest month to swim in Finland?
August is the warmest month in Finland, when the sea averages about 17°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Finland?
The coldest month in Finland is typically February, when the water averages around 3°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Finland without a wetsuit?
The sea in Finland rarely climbs above 20°C, so a wetsuit is recommended year-round for anything longer than a quick dip.
Do I need a wetsuit in Finland?
Outside peak summer the water in Finland drops toward 6°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable. In peak months most swimmers go without.
What is the average sea temperature in Finland?
The long-term annual mean sea temperature in Finland is about 9°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Finland?
The live reading at the top of this page shows the current sea temperature in Finland, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Finland sea temperature by month
Average sea temperatures around Finland for every month of the year, based on long-term Open-Meteo marine climatology.
| Month | Average sea | Swimming comfort |
|---|---|---|
| January | 4.0°C | Too cold for most |
| February | 3.0°C | Too cold for most |
| March | 3.0°C | Too cold for most |
| April | 5.0°C | Too cold for most |
| May | 9.0°C | Too cold for most |
| June | 13.0°C | Too cold for most |
| July | 16.0°C | Bracing — wetsuit advised |
| August ⭐ | 17.0°C | Bracing — wetsuit advised |
| September | 15.0°C | Bracing — wetsuit advised |
| October | 11.0°C | Too cold for most |
| November | 7.0°C | Too cold for most |
| December | 5.0°C | Too cold for most |
Monthly figures are modelled climatology averages, not live readings. How accurate is our data?
Warmest beaches in Finland right now
| Beach | Region | Sea | Swim score |
|---|---|---|---|
| Yyteri | Finnish Coast | 15.7°C | Fair |
| Ruissalo Saaronniemi Beach | Turku Archipelago | 15.5°C | Fair |
| Aurinkolahti Beach | Helsinki | 15.3°C | Fair |
| Degersand Beach Aland | Aland Islands | 15.3°C | Fair |
| Hietaniemi | Finnish Coast | 15.2°C | Fair |
| Uunisaari Beach | Helsinki | 14.9°C | Fair |
| Lilla Holmen Beach | Aland Islands | 14.6°C | Fair |
| Ispoinen Beach | Turku Archipelago | 14.5°C | Fair |
| Kaivopuisto Beach | Helsinki | 14.4°C | Fair |
Sea temperature in Finland — FAQ
How warm is the sea in Finland in September?
The sea off Finland averages about 15.0°C in September, based on long-term monthly averages for this coast.
When is the best time to swim in Finland?
Finland is warmest in August (around 17.0°C) and coldest in February (around 3.0°C). There are typically 0 months a year when the water sits above 22°C.
What is the average yearly sea temperature in Finland?
Across all twelve months, the sea in Finland averages about 9.0°C.
Do you need a wetsuit to swim in Finland?
The sea in Finland stays below 22°C even at its warmest (~17.0°C in August), so a 3/2mm or thicker wetsuit is recommended for longer swims year-round.