Changchun has a four-season, monsoon-influenced, humid continental climate. Winters are long (lasting from November to March), cold, and windy, but dry, due to the influence of the Siberian anticyclone, with a January mean temperature of −14.7 °C (5.5 °F). Spring and autumn are somewhat short transitional periods, with some precipitation, but are usually dry and windy. Summers are hot and humid, with a prevailing southeasterly wind due to the East Asian monsoon; July averages 23.2 °C (73.8 °F). Snow is usually light during the winter, and annual rainfall is heavily concentrated from June to August. With monthly percent possible sunshine ranging from 47 percent in July to 66 percent in January and February, a typical year will see around 2,617 hours of sunshine, and a frost-free period of 140 to 150 days. Extreme temperatures have ranged from −33.0 °C (−27 °F) to 35.7 °C (96 °F).