Deer Lodge, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27.2 °F (low) to 55.6 °F (high). Annual precipitation averages 9.6 Inches. Deer Lodge is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.7 °F | 32.8 °F | 0.32 in. |
| February | 13.4 °F | 36.1 °F | 0.35 in. |
| March | 20.2 °F | 45.3 °F | 0.41 in. |
| April | 26.3 °F | 53.8 °F | 0.83 in. |
| May | 33.9 °F | 63.1 °F | 1.59 in. |
| June | 40.2 °F | 70.5 °F | 2.11 in. |
| July | 45.0 °F | 82.6 °F | 0.86 in. |
| August | 42.8 °F | 81.7 °F | 0.8 in. |
| September | 36.0 °F | 71.2 °F | 0.94 in. |
| October | 27.0 °F | 56.5 °F | 0.63 in. |
| November | 18.4 °F | 41.3 °F | 0.42 in. |
| December | 11.4 °F | 32.0 °F | 0.33 in. |
| Annual | 27.2 °F | 55.6 °F | 9.59 in. |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |