Monmouth Illinois Climate Data

Monthly Average Climate Data for Monmouth Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January14.8 °F31.3 °F1.73 in.
February18.2 °F35.9 °F1.82 in.
March28.9 °F49.2 °F2.53 in.
April39.4 °F62.1 °F3.82 in.
May51.4 °F72.8 °F5.0 in.
June61.0 °F81.7 °F4.74 in.
July64.2 °F84.7 °F3.96 in.
August62.0 °F83.2 °F3.73 in.
September53.8 °F77.6 °F3.84 in.
October42.1 °F65.0 °F2.83 in.
November30.5 °F49.3 °F2.48 in.
December20.6 °F36.6 °F1.98 in.
Annual40.6 °F60.8 °F38.46 in.

Climate Data for Monmouth Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateApr. 21 - Apr. 30
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 ConditionsModerate Drought
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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