Clayton, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 27.7 °F (low) to 56.2 °F (high). Annual precipitation averages 15.9 Inches. Clayton is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Jun. 21 - Jun. 30 through the first frost around July 21 - July 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.5 °F | 30.5 °F | 1.57 in. |
| February | 12.2 °F | 36.4 °F | 1.35 in. |
| March | 20.3 °F | 46.1 °F | 1.41 in. |
| April | 27.2 °F | 54.2 °F | 1.46 in. |
| May | 35.3 °F | 64.0 °F | 1.67 in. |
| June | 41.5 °F | 72.8 °F | 1.55 in. |
| July | 47.4 °F | 84.3 °F | 0.71 in. |
| August | 45.2 °F | 82.6 °F | 0.68 in. |
| September | 38.0 °F | 72.9 °F | 0.94 in. |
| October | 28.8 °F | 58.2 °F | 1.23 in. |
| November | 18.5 °F | 41.9 °F | 1.42 in. |
| December | 9.2 °F | 30.0 °F | 1.92 in. |
| Annual | 27.7 °F | 56.2 °F | 15.91 in. |
| Average First Frost Date | July 21 - July 31 |
| Average Last Frost Date | Jun. 21 - Jun. 30 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |