The land is mostly made of hard granite and gneiss rock, but slate, sandstone, and limestone are also common, and the lowest elevations contain marine deposits. Because of the Gulf Stream and prevailing westerlies, Norway experiences higher temperatures and more precipitation than expected at such northern latitudes, especially along the coast. The mainland experiences four distinct seasons, with colder winters and less precipitation inland. The northernmost part has a mostly maritime Subarctic climate, while Svalbard has an Arctic tundra climate.