Williamson Illinois Climate Data

Monthly Average Climate Data for Williamson Illinois

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-5.9 °C3.1 °C66.29 mm
February-3.9 °C5.9 °C58.42 mm
March0.9 °C11.9 °C81.28 mm
April6.8 °C18.6 °C122.43 mm
May12.9 °C23.8 °C128.78 mm
June17.8 °C28.8 °C112.27 mm
July19.7 °C30.4 °C103.38 mm
August18.5 °C29.9 °C89.15 mm
September13.8 °C26.6 °C84.58 mm
October7.4 °C20 °C82.55 mm
November1.6 °C11.9 °C90.42 mm
December-3.2 °C5.7 °C67.82 mm
Annual7.2 °C18.1 °C1087.37 mm

Climate Data for Williamson Illinois

Average First Frost DateOct. 21 - Oct. 31
Average Last Frost DateApr. 21 - Apr. 30
Average Days With Frost75-100 Days
Plant Hardiness Zone - 2023Zone 6b : -20.6°C to -17.8°C
Plant Hardiness Zone - 2012Zone 6a : -23.3°C to -20.6°C
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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