Gardiner, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.2 °F (low) to 57.5 °F (high). Annual precipitation averages 10.2 Inches. Gardiner is located in USDA Plant Hardiness Zone 5a. 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 | 14.7 °F | 33.3 °F | 0.5 in. |
| February | 15.2 °F | 36.8 °F | 0.44 in. |
| March | 23.0 °F | 46.6 °F | 0.63 in. |
| April | 29.8 °F | 55.4 °F | 0.78 in. |
| May | 37.4 °F | 65.3 °F | 1.45 in. |
| June | 44.3 °F | 74.8 °F | 1.49 in. |
| July | 50.3 °F | 85.6 °F | 0.93 in. |
| August | 48.7 °F | 84.7 °F | 0.66 in. |
| September | 41.5 °F | 74.4 °F | 0.82 in. |
| October | 32.4 °F | 58.5 °F | 0.98 in. |
| November | 22.4 °F | 42.2 °F | 0.89 in. |
| December | 14.7 °F | 32.2 °F | 0.63 in. |
| Annual | 31.2 °F | 57.5 °F | 10.2 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |