Emerson, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.8 °F (low) to 61.7 °F (high). Annual precipitation averages 35.3 Inches. Emerson 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.1 °F | 32.4 °F | 0.81 in. |
| February | 17.1 °F | 37.4 °F | 1.05 in. |
| March | 28.0 °F | 50.6 °F | 1.89 in. |
| April | 38.5 °F | 62.9 °F | 3.37 in. |
| May | 50.9 °F | 73.2 °F | 5.68 in. |
| June | 61.5 °F | 82.5 °F | 5.36 in. |
| July | 65.3 °F | 85.9 °F | 3.85 in. |
| August | 62.6 °F | 84.3 °F | 3.87 in. |
| September | 53.1 °F | 78.2 °F | 3.4 in. |
| October | 40.8 °F | 65.8 °F | 2.94 in. |
| November | 28.3 °F | 49.7 °F | 1.77 in. |
| December | 18.5 °F | 37.1 °F | 1.33 in. |
| Annual | 39.8 °F | 61.7 °F | 35.32 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |