Hartville, Wyoming has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 1.3 °C (low) to 16.5 °C (high). Annual precipitation averages 368.8 Millimeters. Hartville is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.4 °C | 4.2 °C | 7.62 mm |
| February | -8.6 °C | 5.4 °C | 13.46 mm |
| March | -4 °C | 10.6 °C | 21.34 mm |
| April | -0.2 °C | 14.4 °C | 44.96 mm |
| May | 5.2 °C | 19.8 °C | 69.85 mm |
| June | 10.6 °C | 26.4 °C | 59.44 mm |
| July | 14.4 °C | 31.2 °C | 39.12 mm |
| August | 13.1 °C | 30.5 °C | 28.45 mm |
| September | 7.7 °C | 25.2 °C | 33.78 mm |
| October | 0.8 °C | 16.9 °C | 28.96 mm |
| November | -5 °C | 9.4 °C | 10.67 mm |
| December | -9.1 °C | 4.3 °C | 11.18 mm |
| Annual | 1.3 °C | 16.5 °C | 368.83 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |