Oswego Illinois Climate Data

Monthly Average Climate Data for Oswego Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January15.4 °F31.1 °F1.95 in.
February18.2 °F35.1 °F1.88 in.
March28.0 °F47.2 °F2.4 in.
April38.6 °F60.2 °F3.93 in.
May49.6 °F71.2 °F4.76 in.
June59.7 °F80.8 °F4.51 in.
July63.6 °F84.2 °F3.96 in.
August61.9 °F82.4 °F3.93 in.
September54.1 °F76.6 °F3.31 in.
October42.0 °F63.6 °F3.42 in.
November31.2 °F48.9 °F2.53 in.
December21.3 °F36.4 °F2.17 in.
Annual40.3 °F59.8 °F38.75 in.

Climate Data for Oswego 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 5b : -15°F to -10°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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