Forest Lake Illinois Climate Data

Monthly Average Climate Data for Forest Lake Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January14.7 °F30.3 °F1.92 in.
February17.5 °F34.1 °F1.96 in.
March26.8 °F45.5 °F2.32 in.
April37.1 °F57.9 °F3.84 in.
May47.9 °F69.2 °F4.6 in.
June57.9 °F79.3 °F4.54 in.
July63.1 °F83.6 °F3.84 in.
August61.7 °F81.5 °F3.92 in.
September53.7 °F74.7 °F3.42 in.
October42.0 °F61.8 °F3.24 in.
November30.8 °F47.5 °F2.41 in.
December20.7 °F35.4 °F2.1 in.
Annual39.5 °F58.4 °F38.11 in.

Climate Data for Forest Lake Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 1 - May 10
Average Days With Frost125-150 Days
Plant Hardiness Zone - 2023Zone 5b : -15°F to -10°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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