Challis, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 30.7 °F (low) to 57.1 °F (high). Annual precipitation averages 7.3 Inches. Challis is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Aug. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.2 °F | 31.3 °F | 0.47 in. |
| February | 15.4 °F | 37.2 °F | 0.28 in. |
| March | 23.5 °F | 47.4 °F | 0.53 in. |
| April | 30.0 °F | 55.6 °F | 0.65 in. |
| May | 38.0 °F | 65.4 °F | 1.04 in. |
| June | 44.8 °F | 73.9 °F | 1.04 in. |
| July | 51.2 °F | 85.5 °F | 0.47 in. |
| August | 49.0 °F | 83.6 °F | 0.56 in. |
| September | 41.4 °F | 73.7 °F | 0.65 in. |
| October | 31.5 °F | 58.8 °F | 0.55 in. |
| November | 20.8 °F | 42.4 °F | 0.48 in. |
| December | 11.9 °F | 30.7 °F | 0.55 in. |
| Annual | 30.7 °F | 57.1 °F | 7.27 in. |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |