Troy, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 36.8 °F (low) to 58.8 °F (high). Annual precipitation averages 29 Inches. Troy is located in USDA Plant Hardiness Zone 6b. 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 | 26.0 °F | 37.1 °F | 3.4 in. |
| February | 26.7 °F | 41.2 °F | 3.03 in. |
| March | 30.4 °F | 48.6 °F | 2.83 in. |
| April | 35.2 °F | 56.8 °F | 2.81 in. |
| May | 41.5 °F | 66.2 °F | 2.36 in. |
| June | 46.3 °F | 72.1 °F | 1.71 in. |
| July | 49.7 °F | 83.6 °F | 0.64 in. |
| August | 49.3 °F | 84.8 °F | 0.71 in. |
| September | 43.4 °F | 75.0 °F | 1.17 in. |
| October | 36.7 °F | 59.6 °F | 2.63 in. |
| November | 30.8 °F | 44.3 °F | 3.55 in. |
| December | 25.3 °F | 35.9 °F | 4.15 in. |
| Annual | 36.8 °F | 58.8 °F | 28.99 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 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 | Severe Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |