Ottawa Illinois Climate Data

Monthly Average Climate Data for Ottawa Illinois

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-9.1 °C-0.2 °C50.29 mm
February-7.2 °C2.3 °C48.01 mm
March-2 °C9.1 °C63.5 mm
April3.9 °C16.4 °C89.15 mm
May10.2 °C22.6 °C119.63 mm
June15.6 °C27.4 °C116.84 mm
July17.7 °C29.1 °C97.79 mm
August16.6 °C28.1 °C99.06 mm
September12.2 °C25.1 °C84.33 mm
October5.8 °C18.2 °C78.74 mm
November-0.2 °C9.9 °C68.58 mm
December-5.8 °C2.7 °C53.85 mm
Annual4.8 °C15.9 °C969.77 mm

Climate Data for Ottawa Illinois

Average First Frost DateOct. 11 - Oct. 20
Average Last Frost DateMay 1 - May 10
Average Days With Frost125-150 Days
Plant Hardiness Zone - 2023Zone 5b : -26.1°C to -23.3°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