Zhengzhou experiences a monsoon-influenced, four-season humid subtropical climate, with cool, dry winters and hot, humid summers. Spring and autumn are dry and somewhat abbreviated transition periods. The city has an annual mean temperature of 14.35 °C (57.8 °F), with the monthly 24-hour average temperature ranging from 0.1 °C (32.2 °F) in January to 27.0 °C (80.6 °F) in July. The frost-free period lasts on average 220 days. Extremes since 1951 have ranged from −17.9 °C (0 °F) on 2 January 1955, 27 December 1971 and 1 February 1990 to 43.0 °C (109 °F) on 19 July 1966.
Rainfall is primarily produced by the monsoonal low during summer; in winter, when the vast Siberian High dominates due to radiative cooling from further north, the area receives little precipitation. During the summer season, the city is also often affected by tropical depressions, which bring additional amounts of rain. The annual precipitation is about 630 millimetres (25 in). With monthly percent possible sunshine ranging from 45 percent in February and March to 54 percent in May, the city receives 2,182 hours of sunshine per year, which is just under half the possible total.