Hartville, Missouri has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 6.9 °C (low) to 19.5 °C (high). Annual precipitation averages 1173.7 Millimeters. Hartville is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.2 °C | 6.3 °C | 69.34 mm |
| February | -3.2 °C | 8.9 °C | 70.61 mm |
| March | 1.1 °C | 14.1 °C | 105.41 mm |
| April | 6.5 °C | 20.1 °C | 127.76 mm |
| May | 11.7 °C | 24.2 °C | 139.45 mm |
| June | 16.6 °C | 28.6 °C | 106.17 mm |
| July | 18.7 °C | 31.2 °C | 105.92 mm |
| August | 17.8 °C | 30.9 °C | 87.38 mm |
| September | 13.3 °C | 26.9 °C | 100.84 mm |
| October | 6.9 °C | 20.8 °C | 86.87 mm |
| November | 1.3 °C | 13.9 °C | 100.58 mm |
| December | -3.1 °C | 7.9 °C | 73.41 mm |
| Annual | 6.9 °C | 19.5 °C | 1173.74 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |