Deer Lodge, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2.7 °C (low) to 13.1 °C (high). Annual precipitation averages 243.6 Millimeters. 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 | -11.3 °C | 0.4 °C | 8.13 mm |
| February | -10.3 °C | 2.3 °C | 8.89 mm |
| March | -6.6 °C | 7.4 °C | 10.41 mm |
| April | -3.2 °C | 12.1 °C | 21.08 mm |
| May | 1.1 °C | 17.3 °C | 40.39 mm |
| June | 4.6 °C | 21.4 °C | 53.59 mm |
| July | 7.2 °C | 28.1 °C | 21.84 mm |
| August | 6 °C | 27.6 °C | 20.32 mm |
| September | 2.2 °C | 21.8 °C | 23.88 mm |
| October | -2.8 °C | 13.6 °C | 16 mm |
| November | -7.6 °C | 5.2 °C | 10.67 mm |
| December | -11.4 °C | 0 °C | 8.38 mm |
| Annual | -2.7 °C | 13.1 °C | 243.58 mm |
| 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 : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |