Williamson Illinois Climate Data

Monthly Average Climate Data for Williamson Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January21.4 °F37.5 °F2.61 in.
February24.9 °F42.7 °F2.3 in.
March33.7 °F53.5 °F3.2 in.
April44.3 °F65.4 °F4.82 in.
May55.2 °F74.9 °F5.07 in.
June64.1 °F83.8 °F4.42 in.
July67.4 °F86.8 °F4.07 in.
August65.3 °F85.8 °F3.51 in.
September56.9 °F79.9 °F3.33 in.
October45.4 °F68.0 °F3.25 in.
November34.9 °F53.5 °F3.56 in.
December26.2 °F42.2 °F2.67 in.
Annual45 °F64.5 °F42.81 in.

Climate Data for Williamson Illinois

Average First Frost DateOct. 21 - Oct. 31
Average Last Frost DateApr. 11 - Apr. 20
Average Days With Frost75-100 Days
Plant Hardiness Zone - 2023Zone 6b : -5°F to 0°F
Plant Hardiness Zone - 2012Zone 6a : -10°F to -5°F
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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