Romeoville Illinois Climate Data

Monthly Average Climate Data for Romeoville Illinois

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-8.7 °C-0.2 °C54.61 mm
February-7.2 °C1.9 °C50.8 mm
March-1.9 °C8.6 °C64.77 mm
April3.9 °C15.8 °C101.6 mm
May10 °C21.8 °C123.44 mm
June15.6 °C27.1 °C119.63 mm
July17.9 °C29.2 °C107.7 mm
August17.1 °C28.1 °C107.7 mm
September12.8 °C24.9 °C84.33 mm
October6 °C17.6 °C89.41 mm
November0 °C9.6 °C63.5 mm
December-5.6 °C2.7 °C56.39 mm
Annual5 °C15.6 °C1023.88 mm

Climate Data for Romeoville 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 : -23.3°C to -20.6°C
Plant Hardiness Zone - 2012Zone 5b : -26.1°C to -23.3°C
Current Drought ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation