Sun Valley, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 26.2 °F (low) to 55.4 °F (high). Annual precipitation averages 16.9 Inches. Sun Valley is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Aug. 11 - Aug. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.8 °F | 31.9 °F | 2.13 in. |
| February | 10.4 °F | 36.1 °F | 1.53 in. |
| March | 17.9 °F | 43.7 °F | 1.69 in. |
| April | 25.6 °F | 52.5 °F | 1.22 in. |
| May | 33.3 °F | 62.1 °F | 1.75 in. |
| June | 38.7 °F | 71.0 °F | 1.35 in. |
| July | 45.1 °F | 82.4 °F | 0.43 in. |
| August | 43.6 °F | 81.5 °F | 0.59 in. |
| September | 36.8 °F | 71.8 °F | 0.79 in. |
| October | 27.9 °F | 57.9 °F | 1.46 in. |
| November | 17.8 °F | 42.3 °F | 1.42 in. |
| December | 9.1 °F | 31.4 °F | 2.58 in. |
| Annual | 26.2 °F | 55.4 °F | 16.94 in. |
| Average First Frost Date | Aug. 11 - Aug. 20 |
| Average Last Frost Date | Jun. 11 - Jun. 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 | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |