Shanghai has a humid subtropical climate , with an average annual temperature of 15.8 °C (60.4 °F) for urban districts and 15.2–15.7 °C (59.4–60.3 °F) for suburbs. The city experiences four distinct seasons. Winters are chilly and damp—northwesterly winds from Siberia can cause nighttime temperatures to drop below freezing. Each year, there are an average of 6.2 days with snowfall and 2.8 days with snow cover. Summers are hot and humid, and occasional downpours or freak thunderstorms can be expected. On average, 8.7 days exceed 35 °C (95 °F) annually. In summer and the beginning of autumn, the city is susceptible to typhoons.
The most pleasant seasons are generally spring, although changeable and often rainy, and autumn, which is usually sunny and dry. With monthly percent possible sunshine ranging from 34% in March to 54% in August, the city receives 1,895 hours of bright sunshine annually. Extremes since 1951 have ranged from −10.1 °C (14 °F) on 31 January 1977 (unofficial record of −12.1 °C (10 °F) was set on 19 January 1893) to 40.9 °C (106 °F) on 21 July 2017 at a weather station in Xujiahui.