Castalia Iowa Climate Data

Monthly Average Climate Data for Castalia Iowa

Switch Data to Celsius/Metric Units
MonthAvg. LowAvg. HighAvg. Precip
January7.5 °F24.5 °F1.08 in.
February10.8 °F29.0 °F1.16 in.
March23.0 °F42.0 °F2.14 in.
April34.6 °F56.5 °F4.09 in.
May46.6 °F68.5 °F4.92 in.
June57.6 °F78.3 °F5.95 in.
July60.9 °F81.5 °F4.65 in.
August58.2 °F79.6 °F4.27 in.
September49.9 °F73.0 °F3.88 in.
October37.5 °F60.0 °F2.89 in.
November25.8 °F43.4 °F1.97 in.
December14.4 °F30.3 °F1.47 in.
Annual35.6 °F55.6 °F38.47 in.

Climate Data for Castalia 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 : -20°F to -15°F
Plant Hardiness Zone - 2012Zone 4b : -25°F to -20°F
Current Drought ConditionsNormal
Köppen Climate ClassificationDfb - Humid Continental Mild Summer, Wet All Year