Clayton, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from -2.4 °C (low) to 13.4 °C (high). Annual precipitation averages 404.1 Millimeters. 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 | -13.1 °C | -0.8 °C | 39.88 mm |
| February | -11 °C | 2.4 °C | 34.29 mm |
| March | -6.5 °C | 7.8 °C | 35.81 mm |
| April | -2.7 °C | 12.3 °C | 37.08 mm |
| May | 1.8 °C | 17.8 °C | 42.42 mm |
| June | 5.3 °C | 22.7 °C | 39.37 mm |
| July | 8.6 °C | 29.1 °C | 18.03 mm |
| August | 7.3 °C | 28.1 °C | 17.27 mm |
| September | 3.3 °C | 22.7 °C | 23.88 mm |
| October | -1.8 °C | 14.6 °C | 31.24 mm |
| November | -7.5 °C | 5.5 °C | 36.07 mm |
| December | -12.7 °C | -1.1 °C | 48.77 mm |
| Annual | -2.4 °C | 13.4 °C | 404.11 mm |
| 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 : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |