Herron, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 30.5 °F (low) to 56.4 °F (high). Annual precipitation averages 12.4 Inches. Herron is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.0 °F | 28.2 °F | 0.43 in. |
| February | 9.7 °F | 32.3 °F | 0.34 in. |
| March | 19.5 °F | 43.5 °F | 0.49 in. |
| April | 30.4 °F | 56.8 °F | 1.17 in. |
| May | 40.3 °F | 66.6 °F | 1.86 in. |
| June | 48.9 °F | 74.9 °F | 2.68 in. |
| July | 54.3 °F | 85.1 °F | 1.63 in. |
| August | 52.3 °F | 84.5 °F | 0.94 in. |
| September | 42.7 °F | 73.1 °F | 1.11 in. |
| October | 30.9 °F | 57.8 °F | 0.8 in. |
| November | 19.8 °F | 42.2 °F | 0.61 in. |
| December | 10.3 °F | 32.1 °F | 0.38 in. |
| Annual | 30.5 °F | 56.4 °F | 12.44 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |