Portsmouth Iowa Climate Data

Monthly Average Climate Data for Portsmouth Iowa

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January11.3 °F30.0 °F0.78 in.
February15.4 °F34.8 °F1.01 in.
March26.4 °F48.3 °F1.86 in.
April37.2 °F61.3 °F3.49 in.
May49.7 °F71.8 °F4.92 in.
June60.2 °F81.6 °F4.99 in.
July64.0 °F84.8 °F3.8 in.
August61.2 °F82.8 °F4.17 in.
September51.9 °F76.8 °F3.39 in.
October39.7 °F64.2 °F2.6 in.
November27.0 °F47.9 °F1.46 in.
December17.0 °F34.9 °F1.28 in.
Annual38.4 °F59.9 °F33.75 in.

Climate Data for Portsmouth Iowa

Average First Frost DateOct. 1 - Oct. 10
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 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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