Grinnell Iowa Climate Data

Monthly Average Climate Data for Grinnell Iowa

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-10.9 °C-1.9 °C26.67 mm
February-8.8 °C0.6 °C36.58 mm
March-2.9 °C7.8 °C54.61 mm
April3.3 °C15.6 °C100.08 mm
May10.4 °C21.6 °C127.51 mm
June15.9 °C26.8 °C138.43 mm
July18.1 °C28.7 °C106.93 mm
August16.6 °C27.7 °C112.01 mm
September11.7 °C24.4 °C92.96 mm
October5 °C17.2 °C74.17 mm
November-1.7 °C8.5 °C50.8 mm
December-7.4 °C1.2 °C39.37 mm
Annual4.1 °C14.9 °C960.12 mm

Climate Data for Grinnell Iowa

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 11 - May 20
Average Days With Frost125-150 Days
Plant Hardiness Zone - 2023Zone 5b : -26.1°C to -23.3°C
Plant Hardiness Zone - 2012Zone 5a : -28.9°C to -26.1°C
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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