北大西洋海流
Ostrobothnia is located in the borderlands between the humid continental and subarctic climates (Köppen "Dfb/Dfc"). Its winters are moderated by prevailing westerly winds from the mild North Atlantic Current travelling across Norway, Sweden and the Bay of Bothnia. Although the sea tends to easily freeze over in winter during prolonged spells of cold weather due to the low salinity, winters seldom get severely cold.