Lamoni, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.9 °F (low) to 60.4 °F (high). Annual precipitation averages 39.5 Inches. Lamoni is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.4 °F | 31.9 °F | 1.07 in. |
| February | 17.4 °F | 36.9 °F | 1.5 in. |
| March | 28.0 °F | 49.5 °F | 2.41 in. |
| April | 38.9 °F | 61.0 °F | 4.13 in. |
| May | 50.5 °F | 71.1 °F | 5.3 in. |
| June | 60.5 °F | 80.6 °F | 5.29 in. |
| July | 64.8 °F | 84.9 °F | 4.65 in. |
| August | 62.4 °F | 83.5 °F | 4.47 in. |
| September | 53.3 °F | 76.1 °F | 3.78 in. |
| October | 41.1 °F | 63.8 °F | 3.21 in. |
| November | 29.1 °F | 49.2 °F | 2.13 in. |
| December | 18.9 °F | 36.8 °F | 1.58 in. |
| Annual | 39.9 °F | 60.4 °F | 39.52 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 |