Lynnville, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.2 °F (low) to 59.6 °F (high). Annual precipitation averages 37.3 Inches. Lynnville 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 | 12.0 °F | 29.5 °F | 1.05 in. |
| February | 15.7 °F | 34.2 °F | 1.36 in. |
| March | 26.7 °F | 47.4 °F | 2.11 in. |
| April | 38.4 °F | 60.9 °F | 3.9 in. |
| May | 50.6 °F | 71.3 °F | 4.97 in. |
| June | 61.2 °F | 81.2 °F | 5.37 in. |
| July | 64.0 °F | 84.8 °F | 4.29 in. |
| August | 62.0 °F | 82.8 °F | 4.38 in. |
| September | 52.9 °F | 76.2 °F | 3.6 in. |
| October | 40.5 °F | 63.5 °F | 2.76 in. |
| November | 28.8 °F | 47.8 °F | 2.03 in. |
| December | 18.1 °F | 35.1 °F | 1.49 in. |
| Annual | 39.2 °F | 59.6 °F | 37.31 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 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |