Glasgow, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 30.9 °F (low) to 56.2 °F (high). Annual precipitation averages 13.5 Inches. Glasgow 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 | 3.3 °F | 24.7 °F | 0.45 in. |
| February | 7.2 °F | 30.0 °F | 0.37 in. |
| March | 19.3 °F | 43.1 °F | 0.56 in. |
| April | 31.1 °F | 57.9 °F | 1.08 in. |
| May | 42.0 °F | 68.2 °F | 2.14 in. |
| June | 51.5 °F | 76.9 °F | 2.82 in. |
| July | 57.1 °F | 86.3 °F | 1.72 in. |
| August | 55.0 °F | 85.8 °F | 1.26 in. |
| September | 44.8 °F | 74.1 °F | 1.05 in. |
| October | 32.2 °F | 57.8 °F | 1.04 in. |
| November | 18.8 °F | 41.6 °F | 0.52 in. |
| December | 7.9 °F | 28.5 °F | 0.46 in. |
| Annual | 30.9 °F | 56.2 °F | 13.47 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 | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |