Iowa Annual Temperatures and Extremes

City

Avg High Temp

Avg Low Temp 

Avg Annual Temp

Avg # days > 90F Avg # days < 32F  Record High Temp Record Low Temp
Des Moines 59.8 40.2 50.0 23 136 108 / 1983 -26 / 1996
Dubuque 56.1 37.4 46.8 8 148 101 / 1988 -28 / 1970
Sioux City 59.5  37.6 48.5 28 152 108 / 1988 -26 / 1962
Waterloo 58.8 37.0 47.9 28 153 112 / 1936 -33 / 1930
  • Iowa annual average temperature - 47.81 degrees, 36th warmest state in the U.S.
  • Record Hottest year in Iowa - 1931 / Avg temperature 52.06 degrees
  • Record Coldest year in Iowa - 1917 / Avg temperature 43.67 degrees
  • Iowa average Summer temperature (June, July, August) 71.6 F degrees, 25th warmest U.S. summer state
  • Iowa average Winter temperature (December, January, February) 21.7 F degrees, 11th coldest U.S. winter state  

Iowa's Temperature Records

  • Hottest temperature ever recorded: 118 F, Keokuk, southeast Iowa, 7/20/1934
  • Coldest temperature ever recorded: -47 F, Elkader. northeast Iowa, 2/3/1996
  • Hottest location ranked by highest average annual temperature: Keokuk, southeast Iowa, 52.9 F
  • Coldest location ranked by lowest average annual temperature: Cresco, northern Iowa, 44.5 F
  • The summer of 1936 was the hottest summer on record for the United States. On July 13, 1936, the
    average high temperature for all Iowa reporting stations combined was 113 F. Des Moines tied
    its warmest day ever with an average temperature of 95 F. The city also experienced a record 15
    consecutive days on which the temperature rose into the 100s. Other high temperatures reported
    around the state included 110 F at Atlantic and Oskaloosa, 113 F at Keokuk and Washington,
    114 F at Corning and Fairfield, and 115 F at Keosauqua.

The average annual temperature in Iowa ranges from 45 degrees Fahrenheit ( F) in the extreme north to 52 in the southeastern corner of the State. In July, the hottest month, daily temperatures range from morning lows of around 61 and afternoon highs of 82 F in the northeast corner of the State up to lows of 65 and highs of 87 in the southwest. In January, the coldest month, temperatures range from morning lows of 4 and afternoon highs of 22 F in the northwest corner of Iowa up to lows of 15 and highs of 32 in the southeast. 

Extreme temperatures have varied from 118 F at Keokuk on July 20, 1934 to -47 F at Washta on January 12, 1912 and again at Elkader on February 3, 1996. In almost every year at some location in the State, a maximum exceeds 100 F and a minimum of less than -20 occurs. In half of all years, the State maximum exceeds 104 and the minimum -30. The average number of days with maximum temperatures 90 F or higher ranges from only eight days in extreme northeast Iowa up to 36 days in the southwest corner of the State. The number of days with minimum temperatures 0 F or lower ranges from about 28 days along the Minnesota border to around 12 days along the Missouri border.

 

Iowa precipitation averages and extremes, precipitation and temperature data for all U.S. states and Top 10 U.S. climate extremes
Data source: National Climatic Data Center