Brockway, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.5 °C (low) to 13.8 °C (high). Annual precipitation averages 325.4 Millimeters. Brockway 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 | -14.1 °C | -2.1 °C | 6.6 mm |
| February | -12.3 °C | -0.1 °C | 5.59 mm |
| March | -6.6 °C | 6.8 °C | 8.89 mm |
| April | -1 °C | 13.7 °C | 28.45 mm |
| May | 4.6 °C | 19.4 °C | 61.72 mm |
| June | 9.9 °C | 24.4 °C | 67.31 mm |
| July | 13.3 °C | 29.9 °C | 50.55 mm |
| August | 12.3 °C | 29.8 °C | 30.99 mm |
| September | 6.7 °C | 23.6 °C | 29.21 mm |
| October | -0.1 °C | 14.6 °C | 23.37 mm |
| November | -6.7 °C | 6.2 °C | 6.86 mm |
| December | -12.3 °C | -0.3 °C | 5.84 mm |
| Annual | -0.5 °C | 13.8 °C | 325.38 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 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |