Butte, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -3.4 °C (low) to 12 °C (high). Annual precipitation averages 303.3 Millimeters. Butte is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13.1 °C | -0.2 °C | 11.18 mm |
| February | -12.1 °C | 1.4 °C | 11.18 mm |
| March | -7.4 °C | 6.2 °C | 17.53 mm |
| April | -3.6 °C | 10.4 °C | 32.77 mm |
| May | 0.7 °C | 15.6 °C | 47.24 mm |
| June | 4.4 °C | 20.6 °C | 60.96 mm |
| July | 7.3 °C | 26.9 °C | 24.13 mm |
| August | 6.2 °C | 26.4 °C | 22.1 mm |
| September | 2.2 °C | 20.5 °C | 25.91 mm |
| October | -3 °C | 12.5 °C | 23.37 mm |
| November | -8.7 °C | 4.6 °C | 13.97 mm |
| December | -13.3 °C | -0.7 °C | 12.95 mm |
| Annual | -3.4 °C | 12 °C | 303.29 mm |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | Jun. 11 - Jun. 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |