Thornton Illinois Climate Data

Monthly Average Climate Data for Thornton Illinois

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-8.2 °C0.1 °C56.13 mm
February-6.7 °C2.1 °C54.1 mm
March-1.6 °C8.2 °C60.45 mm
April4.1 °C15.2 °C99.31 mm
May10.2 °C21.1 °C113.03 mm
June15.7 °C26.6 °C118.87 mm
July18.4 °C28.8 °C110.49 mm
August17.4 °C27.8 °C104.9 mm
September13.2 °C24.4 °C82.55 mm
October6.5 °C17.4 °C88.39 mm
November0.6 °C9.6 °C69.85 mm
December-5 °C2.9 °C58.42 mm
Annual5.4 °C15.4 °C1016.49 mm

Climate Data for Thornton Illinois

Average First Frost DateOct. 21 - Oct. 31
Average Last Frost DateApr. 21 - Apr. 30
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 ConditionsAbnormally Dry
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
2024 plantmaps.com