Silverton, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 34.4 °F (low) to 56.7 °F (high). Annual precipitation averages 36.9 Inches. Silverton 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. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.0 °F | 34.5 °F | 4.56 in. |
| February | 23.4 °F | 38.8 °F | 3.29 in. |
| March | 27.1 °F | 46.7 °F | 4.13 in. |
| April | 32.3 °F | 55.3 °F | 3.03 in. |
| May | 38.9 °F | 65.7 °F | 2.75 in. |
| June | 44.8 °F | 71.9 °F | 2.7 in. |
| July | 48.8 °F | 82.1 °F | 1.06 in. |
| August | 48.0 °F | 82.3 °F | 1.01 in. |
| September | 41.5 °F | 72.0 °F | 1.48 in. |
| October | 34.1 °F | 55.9 °F | 3.43 in. |
| November | 28.3 °F | 41.3 °F | 4.97 in. |
| December | 22.8 °F | 33.4 °F | 4.52 in. |
| Annual | 34.4 °F | 56.7 °F | 36.93 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| 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 | Severe Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |