Missoula, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.5 °F (low) to 57.7 °F (high). Annual precipitation averages 15.8 Inches. Missoula is located in USDA Plant Hardiness Zone 6a. 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 | 18.6 °F | 33.9 °F | 1.08 in. |
| February | 20.6 °F | 38.6 °F | 0.92 in. |
| March | 26.3 °F | 48.8 °F | 0.99 in. |
| April | 32.2 °F | 56.7 °F | 1.36 in. |
| May | 39.3 °F | 66.3 °F | 1.97 in. |
| June | 45.9 °F | 73.2 °F | 2.59 in. |
| July | 50.8 °F | 85.1 °F | 0.97 in. |
| August | 49.4 °F | 84.6 °F | 1.03 in. |
| September | 42.0 °F | 73.3 °F | 1.19 in. |
| October | 33.0 °F | 57.4 °F | 1.2 in. |
| November | 25.0 °F | 41.8 °F | 1.24 in. |
| December | 18.7 °F | 33.0 °F | 1.21 in. |
| Annual | 33.5 °F | 57.7 °F | 15.75 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 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |