Hammett, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 3.8 °C (low) to 19.6 °C (high). Annual precipitation averages 227.8 Millimeters. Hammett 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 | -4.2 °C | 5 °C | 36.58 mm |
| February | -2.9 °C | 8.9 °C | 17.53 mm |
| March | 0.1 °C | 14.3 °C | 21.84 mm |
| April | 2.6 °C | 18.5 °C | 18.8 mm |
| May | 7.1 °C | 24 °C | 23.11 mm |
| June | 10.7 °C | 29.2 °C | 13.97 mm |
| July | 14.7 °C | 35.6 °C | 4.32 mm |
| August | 13.4 °C | 34.6 °C | 5.08 mm |
| September | 8.3 °C | 28.6 °C | 6.6 mm |
| October | 2.5 °C | 20.3 °C | 17.27 mm |
| November | -1.8 °C | 11.1 °C | 23.11 mm |
| December | -4.6 °C | 4.9 °C | 39.62 mm |
| Annual | 3.8 °C | 19.6 °C | 227.83 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 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |