Aspinwall, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.5 °C (low) to 14.6 °C (high). Annual precipitation averages 854.2 Millimeters. Aspinwall 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 | -11.7 °C | -2.1 °C | 19.56 mm |
| February | -9.4 °C | 0.7 °C | 25.4 mm |
| March | -3.4 °C | 8.1 °C | 46.99 mm |
| April | 2.7 °C | 15.3 °C | 88.65 mm |
| May | 9.5 °C | 21.2 °C | 121.67 mm |
| June | 15.3 °C | 26.8 °C | 127.25 mm |
| July | 17.6 °C | 28.6 °C | 99.82 mm |
| August | 16.2 °C | 27.4 °C | 107.7 mm |
| September | 11.2 °C | 24 °C | 82.8 mm |
| October | 4.6 °C | 17 °C | 65.53 mm |
| November | -2.7 °C | 7.9 °C | 37.34 mm |
| December | -8.4 °C | 0.7 °C | 31.5 mm |
| Annual | 3.5 °C | 14.6 °C | 854.21 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 | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |