Lonepine, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.1 °F (low) to 58.2 °F (high). Annual precipitation averages 11.9 Inches. Lonepine is located in USDA Plant Hardiness Zone 6a. 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 | 20.2 °F | 34.6 °F | 1.03 in. |
| February | 21.2 °F | 38.7 °F | 0.7 in. |
| March | 26.6 °F | 48.1 °F | 0.8 in. |
| April | 32.6 °F | 57.3 °F | 1.07 in. |
| May | 39.7 °F | 67.3 °F | 1.23 in. |
| June | 46.0 °F | 74.0 °F | 1.82 in. |
| July | 51.2 °F | 85.2 °F | 0.67 in. |
| August | 49.7 °F | 84.8 °F | 0.5 in. |
| September | 42.3 °F | 74.0 °F | 0.85 in. |
| October | 33.4 °F | 58.1 °F | 1.0 in. |
| November | 26.2 °F | 42.4 °F | 1.17 in. |
| December | 20.6 °F | 33.9 °F | 1.01 in. |
| Annual | 34.1 °F | 58.2 °F | 11.85 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 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |