Bloomfield, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.8 °C (low) to 13.3 °C (high). Annual precipitation averages 359.4 Millimeters. 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 | -14.4 °C | -2.9 °C | 4.83 mm |
| February | -12.2 °C | -0.6 °C | 6.86 mm |
| March | -7.1 °C | 5.9 °C | 11.43 mm |
| April | -1.3 °C | 13.2 °C | 31.24 mm |
| May | 4.2 °C | 19.1 °C | 64.01 mm |
| June | 9.6 °C | 24.3 °C | 69.6 mm |
| July | 12.8 °C | 29.2 °C | 56.64 mm |
| August | 12 °C | 29.2 °C | 34.8 mm |
| September | 6.6 °C | 23.3 °C | 35.56 mm |
| October | -0.2 °C | 14.1 °C | 27.18 mm |
| November | -6.9 °C | 5.4 °C | 9.65 mm |
| December | -12.2 °C | -0.9 °C | 7.62 mm |
| Annual | -0.8 °C | 13.3 °C | 359.42 mm |
| 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 : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |