Chapin, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.4 °C (low) to 13.6 °C (high). Annual precipitation averages 942.6 Millimeters. Chapin is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.3 °C | -3.9 °C | 23.88 mm |
| February | -11.1 °C | -1.2 °C | 28.96 mm |
| March | -4.5 °C | 5.7 °C | 52.32 mm |
| April | 1.8 °C | 14.2 °C | 101.35 mm |
| May | 8.8 °C | 20.9 °C | 131.06 mm |
| June | 14.8 °C | 26.4 °C | 149.86 mm |
| July | 16.6 °C | 28.1 °C | 116.08 mm |
| August | 15.1 °C | 26.9 °C | 107.19 mm |
| September | 10.1 °C | 23.7 °C | 84.33 mm |
| October | 3.3 °C | 16.1 °C | 65.53 mm |
| November | -3.4 °C | 6.8 °C | 45.21 mm |
| December | -9.6 °C | -0.7 °C | 36.83 mm |
| Annual | 2.4 °C | 13.6 °C | 942.6 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |