Shelley, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 31.6 °F (low) to 57.9 °F (high). Annual precipitation averages 10.8 Inches. Shelley is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.3 °F | 30.1 °F | 0.89 in. |
| February | 16.4 °F | 34.9 °F | 0.61 in. |
| March | 25.6 °F | 47.5 °F | 0.93 in. |
| April | 31.0 °F | 57.5 °F | 1.04 in. |
| May | 38.6 °F | 66.7 °F | 1.48 in. |
| June | 45.0 °F | 75.3 °F | 1.29 in. |
| July | 50.5 °F | 85.8 °F | 0.5 in. |
| August | 48.8 °F | 85.7 °F | 0.6 in. |
| September | 41.4 °F | 75.2 °F | 0.96 in. |
| October | 31.7 °F | 60.3 °F | 1.06 in. |
| November | 22.4 °F | 44.0 °F | 0.73 in. |
| December | 14.2 °F | 31.3 °F | 0.75 in. |
| Annual | 31.6 °F | 57.9 °F | 10.84 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| 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 | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |