Nashua, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 31 °F (low) to 57.2 °F (high). Annual precipitation averages 13.8 Inches. Nashua is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.5 °F | 25.2 °F | 0.34 in. |
| February | 7.8 °F | 30.9 °F | 0.34 in. |
| March | 19.7 °F | 43.9 °F | 0.55 in. |
| April | 31.0 °F | 58.9 °F | 0.94 in. |
| May | 41.9 °F | 69.4 °F | 2.22 in. |
| June | 51.5 °F | 78.1 °F | 3.01 in. |
| July | 57.0 °F | 87.1 °F | 1.94 in. |
| August | 55.2 °F | 87.0 °F | 1.46 in. |
| September | 45.0 °F | 75.5 °F | 0.99 in. |
| October | 32.5 °F | 59.1 °F | 0.96 in. |
| November | 19.0 °F | 42.4 °F | 0.55 in. |
| December | 8.0 °F | 28.9 °F | 0.51 in. |
| Annual | 31 °F | 57.2 °F | 13.81 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| 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 |