Evergreen, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.7 °F (low) to 55.5 °F (high). Annual precipitation averages 16.5 Inches. Evergreen is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.0 °F | 31.7 °F | 1.32 in. |
| February | 19.0 °F | 35.8 °F | 0.96 in. |
| March | 25.0 °F | 44.8 °F | 1.07 in. |
| April | 31.4 °F | 54.9 °F | 1.36 in. |
| May | 39.1 °F | 65.0 °F | 1.83 in. |
| June | 45.5 °F | 71.0 °F | 2.7 in. |
| July | 49.5 °F | 82.0 °F | 1.16 in. |
| August | 47.6 °F | 81.9 °F | 0.89 in. |
| September | 40.3 °F | 70.8 °F | 1.17 in. |
| October | 31.6 °F | 55.3 °F | 1.38 in. |
| November | 25.5 °F | 40.5 °F | 1.33 in. |
| December | 19.3 °F | 31.7 °F | 1.32 in. |
| Annual | 32.7 °F | 55.5 °F | 16.49 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |