Missoula, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.8 °C (low) to 14.3 °C (high). Annual precipitation averages 400.1 Millimeters. 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 | -7.4 °C | 1.1 °C | 27.43 mm |
| February | -6.3 °C | 3.7 °C | 23.37 mm |
| March | -3.2 °C | 9.3 °C | 25.15 mm |
| April | 0.1 °C | 13.7 °C | 34.54 mm |
| May | 4.1 °C | 19.1 °C | 50.04 mm |
| June | 7.7 °C | 22.9 °C | 65.79 mm |
| July | 10.4 °C | 29.5 °C | 24.64 mm |
| August | 9.7 °C | 29.2 °C | 26.16 mm |
| September | 5.6 °C | 22.9 °C | 30.23 mm |
| October | 0.6 °C | 14.1 °C | 30.48 mm |
| November | -3.9 °C | 5.4 °C | 31.5 mm |
| December | -7.4 °C | 0.6 °C | 30.73 mm |
| Annual | 0.8 °C | 14.3 °C | 400.06 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |