Carlton, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33 °F (low) to 59.7 °F (high). Annual precipitation averages 13 Inches. Carlton 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.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 19.0 °F | 35.6 °F | 0.86 in. |
| February | 20.8 °F | 40.3 °F | 0.95 in. |
| March | 26.3 °F | 50.5 °F | 0.79 in. |
| April | 31.7 °F | 59.0 °F | 1.15 in. |
| May | 38.8 °F | 68.5 °F | 1.71 in. |
| June | 45.4 °F | 75.8 °F | 1.72 in. |
| July | 49.7 °F | 87.5 °F | 0.72 in. |
| August | 48.1 °F | 86.3 °F | 0.78 in. |
| September | 41.0 °F | 75.4 °F | 0.85 in. |
| October | 32.1 °F | 59.6 °F | 1.13 in. |
| November | 24.5 °F | 43.4 °F | 1.16 in. |
| December | 19.0 °F | 34.2 °F | 1.21 in. |
| Annual | 33 °F | 59.7 °F | 13.03 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |