Qingdao has a temperate, four-season, monsoon-influenced climate that lies in the transition between the humid subtropical and humid continental regimes, but favouring the former. Winter is cool to cold and windy, but generally dry, with a January average of −0.2 °C (31.6 °F). Summer is generally hot and humid, but very hot days are rare, with an August average of 25.4 °C (77.7 °F). Due to its proximity to the coast and being on a peninsula, it experiences a one-month delayed spring compared to most inland areas of China, and the annual diurnal temperature variation is only 6.3 °C (11.3 °F). Conversely, autumn is milder than inland areas in Shandong. The water temperature peaks at about 25 °C (77 °F) in late August, with swimming possible two months on either side. The annual mean temperature is 12.96 °C (55.3 °F). Extremes since 1951 have ranged from −15.5 °C (4 °F) on 16 January 1958 to 38.9 °C (102 °F) on 15 July 2002.