Broadus, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.8 °F (low) to 60.8 °F (high). Annual precipitation averages 15.1 Inches. Broadus is located in USDA Plant Hardiness Zone 4b. 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 | 10.3 °F | 34.5 °F | 0.36 in. |
| February | 13.9 °F | 38.3 °F | 0.54 in. |
| March | 22.3 °F | 49.1 °F | 0.91 in. |
| April | 31.8 °F | 59.7 °F | 1.76 in. |
| May | 41.3 °F | 68.7 °F | 2.78 in. |
| June | 50.8 °F | 79.4 °F | 2.49 in. |
| July | 57.3 °F | 89.3 °F | 1.83 in. |
| August | 55.2 °F | 88.5 °F | 1.2 in. |
| September | 44.6 °F | 77.9 °F | 1.19 in. |
| October | 32.8 °F | 62.1 °F | 1.12 in. |
| November | 21.2 °F | 46.7 °F | 0.46 in. |
| December | 11.9 °F | 35.9 °F | 0.44 in. |
| Annual | 32.8 °F | 60.8 °F | 15.08 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 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |