Washington Illinois Climate Data

Monthly Average Climate Data for Washington Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January15.8 °F32.5 °F2.18 in.
February19.3 °F37.4 °F2.09 in.
March29.0 °F49.6 °F2.56 in.
April39.8 °F62.7 °F3.81 in.
May51.4 °F73.3 °F4.67 in.
June61.1 °F82.3 °F4.39 in.
July64.3 °F85.4 °F3.73 in.
August62.2 °F83.7 °F3.5 in.
September54.2 °F78.6 °F3.46 in.
October42.6 °F65.5 °F3.15 in.
November31.4 °F50.5 °F2.77 in.
December21.6 °F37.8 °F2.11 in.
Annual41.1 °F61.6 °F38.42 in.

Climate Data for Washington Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 11 - May 20
Average Days With Frost125-150 Days
Plant Hardiness Zone - 2023Zone 6a : -10°F to -5°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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