Harristown Illinois Climate Data

Monthly Average Climate Data for Harristown Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January19.1 °F35.1 °F2.27 in.
February21.5 °F40.1 °F2.01 in.
March30.7 °F51.2 °F2.73 in.
April42.3 °F64.5 °F4.15 in.
May53.6 °F74.4 °F4.61 in.
June61.9 °F83.4 °F4.67 in.
July65.2 °F86.3 °F3.79 in.
August63.6 °F84.7 °F3.29 in.
September54.8 °F79.6 °F3.15 in.
October43.1 °F66.9 °F3.28 in.
November32.4 °F51.8 °F3.08 in.
December24.7 °F39.9 °F2.37 in.
Annual42.7 °F63.2 °F39.4 in.

Climate Data for Harristown Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateApr. 21 - Apr. 30
Average Days With Frost100-125 Days
Plant Hardiness Zone - 2023Zone 6a : -10°F to -5°F
Plant Hardiness Zone - 2012Zone 6a : -10°F to -5°F
Current Drought ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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