Bloomfield, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 30.6 °F (low) to 55.9 °F (high). Annual precipitation averages 14.2 Inches. Bloomfield 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 | 6.0 °F | 26.7 °F | 0.19 in. |
| February | 10.1 °F | 31.0 °F | 0.27 in. |
| March | 19.2 °F | 42.6 °F | 0.45 in. |
| April | 29.6 °F | 55.7 °F | 1.23 in. |
| May | 39.6 °F | 66.3 °F | 2.52 in. |
| June | 49.3 °F | 75.7 °F | 2.74 in. |
| July | 55.0 °F | 84.5 °F | 2.23 in. |
| August | 53.6 °F | 84.5 °F | 1.37 in. |
| September | 43.9 °F | 73.9 °F | 1.4 in. |
| October | 31.6 °F | 57.3 °F | 1.07 in. |
| November | 19.5 °F | 41.7 °F | 0.38 in. |
| December | 10.0 °F | 30.3 °F | 0.3 in. |
| Annual | 30.6 °F | 55.9 °F | 14.15 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 | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |