McHenry Illinois Climate Data

Monthly Average Climate Data for McHenry Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January13.3 °F29.2 °F1.78 in.
February16.1 °F33.1 °F1.84 in.
March25.7 °F44.6 °F2.21 in.
April36.2 °F57.7 °F3.75 in.
May47.1 °F69.3 °F4.68 in.
June57.2 °F79.0 °F4.92 in.
July61.9 °F83.0 °F3.88 in.
August60.3 °F81.2 °F3.87 in.
September52.2 °F74.5 °F3.58 in.
October40.5 °F61.4 °F3.14 in.
November29.8 °F46.9 °F2.41 in.
December19.5 °F34.6 °F2.0 in.
Annual38.3 °F57.9 °F38.06 in.

Climate Data for McHenry Illinois

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