canIswim

What wetsuit do you need in Finland?

The one suit that covers most of the swimming season, for 15 coastal cities in Finland.

City Coldest Warmest One suit for the season
Helsinki 0.9°C Feb 17.8°C Aug 5/4 mm, and not alone
Vantaa 0.7°C Feb 17.8°C Aug 5/4 mm, and not alone
Oulu -0.1°C Feb 18.7°C Jul 5/4 mm, and not alone
Pori 0.3°C Feb 17.7°C Aug 5/4 mm, and not alone
Vaasa -0.1°C Feb 17.4°C Jul 5/4 mm, and not alone
Kotka 0.3°C Feb 18.6°C Aug 5/4 mm, and not alone
Kokkola 0.0°C Feb 16.9°C Aug 5/4 mm, and not alone
Kirkkonummi 1.0°C Feb 17.8°C Aug 5/4 mm, and not alone
Rauma 0.4°C Feb 17.9°C Aug 5/4 mm, and not alone
Raahe 0.0°C Feb 17.0°C Aug 5/4 mm, and not alone
Tornio -0.1°C Feb 17.6°C Jul 5/4 mm, and not alone
Jakobstad 0.0°C Feb 16.8°C Aug 5/4 mm, and not alone
Kemi -0.1°C Feb 18.0°C Jul 5/4 mm, and not alone
Uusikaupunki 0.7°C Feb 17.7°C Aug 5/4 mm, and not alone
Närpes 0.4°C Feb 17.1°C Aug 5/4 mm, and not alone

Thicknesses above are for swimming. Surfing the same water wants a step more — most of a session is spent sitting still in the wind rather than moving and immersed. Each city page gives both, along with when you need boots, gloves and a hood.

Boots below 14°C, gloves below 12°C, a hood below 10°C. Where the numbers come from