Lewistown, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 43.1 °F (low) to 63.1 °F (high). Annual precipitation averages 39.3 Inches. Lewistown is located in USDA Plant Hardiness Zone 6a. 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 | 18.1 °F | 35.0 °F | 1.52 in. |
| February | 21.4 °F | 39.7 °F | 1.89 in. |
| March | 31.5 °F | 52.0 °F | 2.42 in. |
| April | 42.3 °F | 64.4 °F | 3.91 in. |
| May | 53.4 °F | 73.9 °F | 5.28 in. |
| June | 63.1 °F | 83.0 °F | 4.72 in. |
| July | 66.6 °F | 86.8 °F | 4.4 in. |
| August | 64.4 °F | 85.4 °F | 3.78 in. |
| September | 56.0 °F | 78.9 °F | 3.69 in. |
| October | 44.4 °F | 66.6 °F | 3.32 in. |
| November | 33.0 °F | 52.1 °F | 2.49 in. |
| December | 23.4 °F | 39.5 °F | 1.86 in. |
| Annual | 43.1 °F | 63.1 °F | 39.28 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |