Joliet Illinois Climate Data

Monthly Average Climate Data for Joliet Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January16.3 °F31.6 °F2.08 in.
February19.3 °F35.7 °F1.94 in.
March28.8 °F47.6 °F2.43 in.
April39.1 °F60.8 °F3.89 in.
May50.0 °F71.6 °F4.78 in.
June60.2 °F81.1 °F4.64 in.
July63.9 °F84.5 °F4.34 in.
August62.5 °F82.8 °F4.14 in.
September54.8 °F77.2 °F3.38 in.
October42.8 °F64.1 °F3.33 in.
November31.8 °F49.3 °F2.45 in.
December22.2 °F37.0 °F2.13 in.
Annual41 °F60.3 °F39.53 in.

Climate Data for Joliet Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 1 - May 10
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