Aspinwall, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.2 °F (low) to 58.3 °F (high). Annual precipitation averages 33.6 Inches. 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 | 11.0 °F | 28.3 °F | 0.77 in. |
| February | 15.1 °F | 33.2 °F | 1.0 in. |
| March | 25.9 °F | 46.5 °F | 1.85 in. |
| April | 36.8 °F | 59.5 °F | 3.49 in. |
| May | 49.1 °F | 70.2 °F | 4.79 in. |
| June | 59.6 °F | 80.2 °F | 5.01 in. |
| July | 63.6 °F | 83.4 °F | 3.93 in. |
| August | 61.1 °F | 81.3 °F | 4.24 in. |
| September | 52.1 °F | 75.2 °F | 3.26 in. |
| October | 40.3 °F | 62.6 °F | 2.58 in. |
| November | 27.1 °F | 46.3 °F | 1.47 in. |
| December | 16.8 °F | 33.2 °F | 1.24 in. |
| Annual | 38.2 °F | 58.3 °F | 33.63 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |