Lynnville, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4 °C (low) to 15.3 °C (high). Annual precipitation averages 947.7 Millimeters. 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 | -11.1 °C | -1.4 °C | 26.67 mm |
| February | -9.1 °C | 1.2 °C | 34.54 mm |
| March | -2.9 °C | 8.6 °C | 53.59 mm |
| April | 3.6 °C | 16.1 °C | 99.06 mm |
| May | 10.3 °C | 21.8 °C | 126.24 mm |
| June | 16.2 °C | 27.3 °C | 136.4 mm |
| July | 17.8 °C | 29.3 °C | 108.97 mm |
| August | 16.7 °C | 28.2 °C | 111.25 mm |
| September | 11.6 °C | 24.6 °C | 91.44 mm |
| October | 4.7 °C | 17.5 °C | 70.1 mm |
| November | -1.8 °C | 8.8 °C | 51.56 mm |
| December | -7.7 °C | 1.7 °C | 37.85 mm |
| Annual | 4 °C | 15.3 °C | 947.67 mm |
| 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 : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |