Iowa lies in the humid continental zone and generally has hot summers, cold winters, and wet springs.

Temperatures vary widely during the year, with an annual average of 49°F (9°C). The state averages 166 days of full sunshine and 199 cloudy or partly cloudy days. Des Moines, in the central part of the state, has a normal daily maximum temperature of 86°F (30°C) in July and a normal daily minimum of 10°F (–4°C) in January. The record low temperature for the state is –47°F (–44°C), established at Washta on 12 January 1912 and recorded again on Elkader on 3 February 1996; the record high is 118°F (48°C), registered at Keokuk on 20 July 1934. Annual precipitation averaged 34.7 in (88 cm) at Des Moines (1971–2000); statewide, snowfall averages 30 in (76 cm) annually and relative humidity averages 72%.