Unionville, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40 °F (low) to 61 °F (high). Annual precipitation averages 41.6 Inches. Unionville 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 | 13.9 °F | 32.2 °F | 1.3 in. |
| February | 17.7 °F | 37.2 °F | 1.73 in. |
| March | 28.1 °F | 49.9 °F | 2.56 in. |
| April | 39.1 °F | 62.0 °F | 4.06 in. |
| May | 50.4 °F | 71.7 °F | 5.43 in. |
| June | 60.2 °F | 81.2 °F | 5.91 in. |
| July | 64.7 °F | 85.5 °F | 4.88 in. |
| August | 62.1 °F | 84.1 °F | 4.53 in. |
| September | 53.4 °F | 76.9 °F | 4.1 in. |
| October | 41.4 °F | 64.0 °F | 3.01 in. |
| November | 29.4 °F | 49.6 °F | 2.33 in. |
| December | 19.5 °F | 37.3 °F | 1.71 in. |
| Annual | 40 °F | 61 °F | 41.55 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 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 |