Grafton Iowa Climate Data

Monthly Average Climate Data for Grafton Iowa

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January6.4 °F23.2 °F1.0 in.
February10.4 °F27.7 °F1.1 in.
March22.6 °F40.2 °F1.94 in.
April34.6 °F55.7 °F3.87 in.
May46.9 °F68.0 °F5.1 in.
June57.8 °F77.9 °F5.45 in.
July61.1 °F81.0 °F4.68 in.
August58.4 °F78.7 °F4.09 in.
September49.8 °F72.6 °F3.5 in.
October37.2 °F59.0 °F2.66 in.
November25.0 °F42.7 °F1.75 in.
December13.5 °F28.9 °F1.37 in.
Annual35.3 °F54.6 °F36.51 in.

Climate Data for Grafton Iowa

Average First Frost DateOct. 1 - Oct. 10
Average Last Frost DateMay 11 - May 20
Average Days With Frost150-180 Days
Plant Hardiness Zone - 2023Zone 5a : -20°F to -15°F
Plant Hardiness Zone - 2012Zone 5a : -20°F to -15°F
Current Drought ConditionsModerate Drought
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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