Glenns Ferry, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 3.3 °C (low) to 19.5 °C (high). Annual precipitation averages 236.7 Millimeters. Glenns Ferry is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.6 °C | 4.9 °C | 41.66 mm |
| February | -3.4 °C | 8.7 °C | 17.27 mm |
| March | -0.4 °C | 14.2 °C | 21.84 mm |
| April | 2.2 °C | 18.4 °C | 18.8 mm |
| May | 6.7 °C | 24 °C | 23.37 mm |
| June | 10.3 °C | 29.2 °C | 13.72 mm |
| July | 14 °C | 35.6 °C | 4.32 mm |
| August | 12.6 °C | 34.6 °C | 5.84 mm |
| September | 7.5 °C | 28.6 °C | 6.6 mm |
| October | 1.8 °C | 20.2 °C | 17.53 mm |
| November | -2.4 °C | 11.1 °C | 23.11 mm |
| December | -5.1 °C | 4.8 °C | 42.67 mm |
| Annual | 3.3 °C | 19.5 °C | 236.73 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |