Hartville, Wyoming has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 34.3 °F (low) to 61.8 °F (high). Annual precipitation averages 14.5 Inches. 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 | 15.0 °F | 39.5 °F | 0.3 in. |
| February | 16.6 °F | 41.7 °F | 0.53 in. |
| March | 24.8 °F | 51.1 °F | 0.84 in. |
| April | 31.6 °F | 57.9 °F | 1.77 in. |
| May | 41.3 °F | 67.6 °F | 2.75 in. |
| June | 51.0 °F | 79.6 °F | 2.34 in. |
| July | 58.0 °F | 88.1 °F | 1.54 in. |
| August | 55.5 °F | 86.9 °F | 1.12 in. |
| September | 45.8 °F | 77.4 °F | 1.33 in. |
| October | 33.4 °F | 62.5 °F | 1.14 in. |
| November | 23.0 °F | 49.0 °F | 0.42 in. |
| December | 15.6 °F | 39.7 °F | 0.44 in. |
| Annual | 34.3 °F | 61.8 °F | 14.52 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |