Jinan has a humid subtropical , considering a normal isotherm of −3 °C, or a humid continental climate , considering an isotherm of 0 °C but favoring the former, with four well-defined seasons. The city is dry and nearly rainless in spring, hot and rainy in summer, crisp in autumn and dry and cold (with little snow) in winter. The average annual temperature is 14.70 °C (58.5 °F), and the annual precipitation is around slightly above 670 millimetres (26.4 in), with a strong summer maximum, and high variability from year to year. January is the coldest and driest month, with a mean temperature of −0.4 °C (31.3 °F) and 5.7 millimetres (0.22 in) of equivalent rainfall. July is the hottest and wettest month, the corresponding numbers are 27.5 °C (81.5 °F), and 201.3 mm (7.93 in). With monthly percent possible sunshine ranging from 48 percent in July to 63 percent in May, the city receives 2,547 hours of bright sunshine annually.
Due to the mountains to the south of the city, temperature inversions are common, occurring on about 200 days per year. The high precipitation for northern Chinese standards, in tandem with the topography (mountains surrounding the city on three sides), leads to particularly oppressive summer weather and the city being named as a candidate for the fourth “furnace”, c.e. Three Furnaces.
Extremes since 1951 have ranged from −19.7 °C (−3 °F) on 17 January 1953 to 42.5 °C (109 °F) on 24 July 1955.