Grafton Iowa Climate Data

Monthly Average Climate Data for Grafton Iowa

Switch Data to Fahrenheit
MonthAvg. LowAvg. HighAvg. Precip
January-14.2 °C-4.9 °C25.4 mm
February-12 °C-2.4 °C27.94 mm
March-5.2 °C4.6 °C49.28 mm
April1.4 °C13.2 °C98.3 mm
May8.3 °C20 °C129.54 mm
June14.3 °C25.5 °C138.43 mm
July16.2 °C27.2 °C118.87 mm
August14.7 °C25.9 °C103.89 mm
September9.9 °C22.6 °C88.9 mm
October2.9 °C15 °C67.56 mm
November-3.9 °C5.9 °C44.45 mm
December-10.3 °C-1.7 °C34.8 mm
Annual1.8 °C12.6 °C927.36 mm

Climate Data for Grafton Iowa

Average First Frost DateOct. 1 - Oct. 10
Average Last Frost DateMay 21 - May 31
Average Days With Frost150-180 Days
Plant Hardiness Zone - 2023Zone 5a : -28.9°C to -26.1°C
Plant Hardiness Zone - 2012Zone 5a : -28.9°C to -26.1°C
Current Drought ConditionsNormal
Köppen Climate ClassificationDfa - Humid Continental Hot Summers With Year Around Precipitation
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