Winthrop Harbor Illinois Climate Data

Monthly Average Climate Data for Winthrop Harbor Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January16.2 °F30.2 °F1.94 in.
February18.9 °F33.2 °F1.89 in.
March27.8 °F42.5 °F2.3 in.
April37.6 °F52.8 °F3.96 in.
May47.4 °F63.8 °F4.23 in.
June57.6 °F73.8 °F4.11 in.
July64.3 °F79.7 °F3.49 in.
August63.7 °F78.6 °F3.54 in.
September56.0 °F72.1 °F3.42 in.
October44.2 °F60.2 °F3.19 in.
November32.6 °F47.2 °F2.38 in.
December22.3 °F35.7 °F2.07 in.
Annual40.7 °F55.8 °F36.52 in.

Climate Data for Winthrop Harbor Illinois

Average First Frost DateOct. 21 - Oct. 31
Average Last Frost DateMay 11 - May 20
Average Days With Frost100-125 Days
Plant Hardiness Zone - 2023Zone 6a : -10°F to -5°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsModerate Drought
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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