According to the Köppen climate classification system, the best definition for Mount Rainier National Park is Mediterranean-influenced Subarctic climate (‘'Dsc''). ‘'Dsc climates are defined by their coldest month averaging below 0 °C (32 °F), 1-3 months averaging above 10 °C (50 °F), at least three times as much precipitation in the wettest month of winter as in the driest month of summer. According to the United States Department of Agriculture, the Plant Hardiness zone at Sunrise Visitor Center ( elevation) is 6a with an average annual extreme minimum temperature of -5.5 °F (-20.8 °C).