Grafton Illinois Climate Data

Monthly Average Climate Data for Grafton Illinois

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January21.9 °F38.6 °F2.44 in.
February25.4 °F44.1 °F2.23 in.
March34.1 °F54.6 °F3.24 in.
April45.0 °F66.6 °F4.66 in.
May56.0 °F75.7 °F4.77 in.
June64.9 °F84.3 °F4.23 in.
July68.6 °F87.8 °F3.77 in.
August66.4 °F86.7 °F3.63 in.
September57.9 °F80.4 °F3.27 in.
October46.2 °F68.5 °F3.06 in.
November35.3 °F54.8 °F3.33 in.
December26.5 °F43.3 °F2.6 in.
Annual45.7 °F65.5 °F41.23 in.

Climate Data for Grafton Illinois

Average First Frost DateOct. 21 - Oct. 31
Average Last Frost DateApr. 11 - Apr. 20
Average Days With Frost75-100 Days
Plant Hardiness Zone - 2023Zone 6b : -5°F to 0°F
Plant Hardiness Zone - 2012Zone 6a : -10°F to -5°F
Current Drought ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
2024 plantmaps.com