The climate of Sweden varies, with air currents produced by the Atlantic Ocean make the western coast and southern region of Sweden temperate, moist and mild while the northernmost areas and eastern border experience much colder temperatures year-round. Most of Sweden has four distinct seasons, with more precipitation, higher temperatures and longer periods of sunlight during the summer months.
The seasonal variations and general climate of Sweden derive influence from the country's northern latitude and physical geography, which includes tall mountains along the western coast and long, flat plateaus. Having a northern latitude produces extreme differences between hours of sunlight during the winter and summer months. In the winter, days in Sweden have few hours of sunlight. Summer days, however, are considerably longer for all parts of the country. North of the Arctic Circle, winter months bring close to 24 hours of darkness, but summer days see up to 24 hours of sunlight. The mountains and plateaus along the west coast and interior help to trap moisture and allow the temperate winds of the Atlantic Ocean to sweep over the interior, producing a mild climate. In addition to land, geography and weather influences the waters around Sweden. Seas on the southwest coast rarely freeze, but waters in the Baltic Sea, which lies off the northwest coast, remain frozen through much of the winter.