Union Iowa Climate Data

Monthly Average Climate Data for Union Iowa

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January10.2 °F27.2 °F0.97 in.
February14.2 °F31.9 °F1.12 in.
March25.6 °F45.0 °F2.08 in.
April37.0 °F59.5 °F3.77 in.
May49.4 °F70.7 °F5.03 in.
June60.0 °F80.4 °F5.64 in.
July63.2 °F83.6 °F4.3 in.
August60.5 °F81.5 °F4.3 in.
September51.7 °F75.7 °F3.41 in.
October39.4 °F62.1 °F2.63 in.
November27.2 °F46.1 °F1.9 in.
December16.4 °F32.8 °F1.47 in.
Annual37.9 °F58 °F36.62 in.

Climate Data for Union Iowa

Average First Frost DateOct. 1 - Oct. 10
Average Last Frost DateMay 1 - May 10
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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