Sun Valley, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from -3.2 °C (low) to 13 °C (high). Annual precipitation averages 430.3 Millimeters. 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 | -13.4 °C | -0.1 °C | 54.1 mm |
| February | -12 °C | 2.3 °C | 38.86 mm |
| March | -7.8 °C | 6.5 °C | 42.93 mm |
| April | -3.6 °C | 11.4 °C | 30.99 mm |
| May | 0.7 °C | 16.7 °C | 44.45 mm |
| June | 3.7 °C | 21.7 °C | 34.29 mm |
| July | 7.3 °C | 28 °C | 10.92 mm |
| August | 6.4 °C | 27.5 °C | 14.99 mm |
| September | 2.7 °C | 22.1 °C | 20.07 mm |
| October | -2.3 °C | 14.4 °C | 37.08 mm |
| November | -7.9 °C | 5.7 °C | 36.07 mm |
| December | -12.7 °C | -0.3 °C | 65.53 mm |
| Annual | -3.2 °C | 13 °C | 430.28 mm |
| 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 : -26.1°C to -23.3°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 |