In the Coastal Lapand, in the most northern parts of of the Baltic Sea, the temperatures in the air are greatly affected by the sea temperature but also by the ten large rivers that flow from the mountains around the sea and out into the Baltic Sea. When the sun gasps and warms the water in the rivers, the sea also gets warm – especially if the winds are from the south and moderate. Then the warm surface water stays in the sea. When the area is also “occupied” by high pressure and light winds from the northeast, something called the “Russian heat” comes. It is solar-heated air that sweeps down from Russia’s mainland and then it’s time for shorts and a T-shirt. It will be 25 degrees hot, calculated in Celsius. Sometimes also 30 or 35 degrees. The bathing water in rivers, lakes and seas that were frozen in April can offer temperatures of 20-25 degrees Celsius but also closer to 30. More normal is 15-18 degrees.