Humeston, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.5 °F (low) to 60.2 °F (high). Annual precipitation averages 38.4 Inches. Humeston is located in USDA Plant Hardiness Zone 5b. 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 | 13.0 °F | 31.4 °F | 1.04 in. |
| February | 16.9 °F | 36.1 °F | 1.37 in. |
| March | 27.7 °F | 49.0 °F | 2.18 in. |
| April | 38.5 °F | 61.0 °F | 4.0 in. |
| May | 50.3 °F | 70.9 °F | 5.4 in. |
| June | 60.3 °F | 80.4 °F | 5.3 in. |
| July | 64.7 °F | 84.9 °F | 4.45 in. |
| August | 62.0 °F | 83.1 °F | 4.43 in. |
| September | 52.9 °F | 76.2 °F | 3.79 in. |
| October | 40.8 °F | 63.7 °F | 2.97 in. |
| November | 28.7 °F | 48.9 °F | 2.02 in. |
| December | 18.6 °F | 36.6 °F | 1.44 in. |
| Annual | 39.5 °F | 60.2 °F | 38.39 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |