Harristown Illinois Climate Data

Monthly Average Climate Data for Harristown Illinois

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-7.2 °C1.7 °C57.66 mm
February-5.8 °C4.5 °C51.05 mm
March-0.7 °C10.7 °C69.34 mm
April5.7 °C18.1 °C105.41 mm
May12 °C23.6 °C117.09 mm
June16.6 °C28.6 °C118.62 mm
July18.4 °C30.2 °C96.27 mm
August17.6 °C29.3 °C83.57 mm
September12.7 °C26.4 °C80.01 mm
October6.2 °C19.4 °C83.31 mm
November0.2 °C11 °C78.23 mm
December-4.1 °C4.4 °C60.2 mm
Annual6 °C17.3 °C1000.76 mm

Climate Data for Harristown Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 1 - May 10
Average Days With Frost100-125 Days
Plant Hardiness Zone - 2023Zone 6a : -23.3°C to -20.6°C
Plant Hardiness Zone - 2012Zone 6a : -23.3°C to -20.6°C
Current Drought ConditionsModerate Drought
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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