Longtown, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45.7 °F (low) to 66.8 °F (high). Annual precipitation averages 46.1 Inches. Longtown is located in USDA Plant Hardiness Zone 6b. 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 | 23.5 °F | 41.5 °F | 2.94 in. |
| February | 26.8 °F | 46.9 °F | 2.88 in. |
| March | 35.0 °F | 56.7 °F | 3.96 in. |
| April | 44.9 °F | 67.8 °F | 5.15 in. |
| May | 55.1 °F | 76.5 °F | 5.56 in. |
| June | 63.7 °F | 84.9 °F | 4.31 in. |
| July | 67.7 °F | 88.0 °F | 3.87 in. |
| August | 65.3 °F | 87.1 °F | 3.24 in. |
| September | 57.2 °F | 80.8 °F | 3.26 in. |
| October | 45.8 °F | 70.0 °F | 3.4 in. |
| November | 35.8 °F | 56.5 °F | 4.24 in. |
| December | 27.3 °F | 45.1 °F | 3.27 in. |
| Annual | 45.7 °F | 66.8 °F | 46.08 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 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |