Big Sky, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 23 °F (low) to 49.6 °F (high). Annual precipitation averages 28.8 Inches. Big Sky is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.0 °F | 28.3 °F | 2.22 in. |
| February | 8.0 °F | 31.2 °F | 1.96 in. |
| March | 14.2 °F | 38.8 °F | 2.08 in. |
| April | 21.1 °F | 46.5 °F | 2.48 in. |
| May | 29.4 °F | 55.8 °F | 3.67 in. |
| June | 35.3 °F | 64.6 °F | 3.66 in. |
| July | 40.9 °F | 75.4 °F | 1.93 in. |
| August | 39.4 °F | 75.1 °F | 1.95 in. |
| September | 33.5 °F | 65.4 °F | 1.88 in. |
| October | 24.7 °F | 51.1 °F | 2.38 in. |
| November | 14.5 °F | 35.5 °F | 2.08 in. |
| December | 7.1 °F | 26.9 °F | 2.52 in. |
| Annual | 23 °F | 49.6 °F | 28.81 in. |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |