Troy, Montana has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 35.6 °F (low) to 59.4 °F (high). Annual precipitation averages 23 Inches. Troy is located in USDA Plant Hardiness Zone 6b. 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 | 23.2 °F | 34.7 °F | 2.72 in. |
| February | 23.7 °F | 40.2 °F | 1.85 in. |
| March | 28.2 °F | 49.9 °F | 2.16 in. |
| April | 33.4 °F | 59.6 °F | 1.74 in. |
| May | 40.7 °F | 69.9 °F | 1.87 in. |
| June | 47.0 °F | 76.0 °F | 2.17 in. |
| July | 50.7 °F | 86.8 °F | 0.63 in. |
| August | 49.3 °F | 86.7 °F | 0.72 in. |
| September | 42.7 °F | 75.2 °F | 1.06 in. |
| October | 35.2 °F | 57.4 °F | 2.14 in. |
| November | 29.5 °F | 42.4 °F | 3.33 in. |
| December | 23.8 °F | 34.1 °F | 2.64 in. |
| Annual | 35.6 °F | 59.4 °F | 23.03 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 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |