Salmon, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Annual precipitation averages 236.7 Millimeters. Salmon 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10 °C | -0.7 °C | 13.97 mm |
| February | -8.2 °C | 2.9 °C | 10.41 mm |
| March | -3.4 °C | 9.9 °C | 13.97 mm |
| April | -0.2 °C | 15 °C | 18.8 mm |
| May | 3.9 °C | 20.2 °C | 34.04 mm |
| June | 7.5 °C | 24.6 °C | 36.32 mm |
| July | 10.6 °C | 30.7 °C | 17.27 mm |
| August | 9.3 °C | 29.9 °C | 14.99 mm |
| September | 5.1 °C | 24.2 °C | 19.81 mm |
| October | -0.1 °C | 15.1 °C | 22.35 mm |
| November | -5 °C | 5.6 °C | 16.26 mm |
| December | -9.8 °C | -0.9 °C | 18.54 mm |
| Annual | -0 °C | 14.7 °C | 236.73 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |