DeKalb Illinois Climate Data

Monthly Average Climate Data for DeKalb Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January12.8 °F28.6 °F1.7 in.
February16.3 °F32.8 °F1.73 in.
March26.3 °F45.1 °F2.22 in.
April36.8 °F58.6 °F3.44 in.
May48.6 °F70.1 °F4.9 in.
June58.5 °F79.7 °F4.58 in.
July62.3 °F82.7 °F3.82 in.
August60.1 °F80.9 °F3.95 in.
September51.7 °F75.0 °F3.37 in.
October40.0 °F62.2 °F2.97 in.
November29.4 °F46.9 °F2.37 in.
December18.9 °F34.1 °F1.98 in.
Annual38.5 °F58.1 °F37.03 in.

Climate Data for DeKalb 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 : -15°F to -10°F
Plant Hardiness Zone - 2012Zone 5b : -15°F to -10°F
Current Drought ConditionsAbnormally Dry
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation