Grayslake Illinois Climate Data

Monthly Average Climate Data for Grayslake Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January14.5 °F29.6 °F1.94 in.
February17.2 °F33.5 °F1.97 in.
March26.7 °F44.4 °F2.3 in.
April36.9 °F56.8 °F3.9 in.
May47.7 °F68.2 °F4.45 in.
June57.8 °F78.1 °F4.57 in.
July62.8 °F82.5 °F3.79 in.
August61.4 °F80.8 °F3.73 in.
September53.6 °F74.0 °F3.55 in.
October42.0 °F61.1 °F3.21 in.
November30.9 °F47.0 °F2.43 in.
December20.7 °F35.0 °F2.15 in.
Annual39.4 °F57.6 °F37.99 in.

Climate Data for Grayslake 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 ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation