Montana City, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.3 °F (low) to 56.7 °F (high). Annual precipitation averages 14.2 Inches. Montana City is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 14.1 °F | 33.7 °F | 0.56 in. |
| February | 16.2 °F | 37.0 °F | 0.67 in. |
| March | 22.7 °F | 46.1 °F | 0.74 in. |
| April | 29.8 °F | 54.7 °F | 1.52 in. |
| May | 38.1 °F | 64.1 °F | 2.34 in. |
| June | 45.0 °F | 72.7 °F | 2.45 in. |
| July | 50.5 °F | 83.8 °F | 1.21 in. |
| August | 48.5 °F | 83.1 °F | 1.15 in. |
| September | 41.6 °F | 71.8 °F | 1.23 in. |
| October | 31.9 °F | 56.7 °F | 1.07 in. |
| November | 22.8 °F | 42.6 °F | 0.74 in. |
| December | 14.7 °F | 33.5 °F | 0.53 in. |
| Annual | 31.3 °F | 56.7 °F | 14.21 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |