Ammon, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.3 °C (low) to 14.1 °C (high). Annual precipitation averages 316.8 Millimeters. Ammon is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.8 °C | -1.6 °C | 28.96 mm |
| February | -9 °C | 1.2 °C | 20.83 mm |
| March | -3.8 °C | 8.3 °C | 27.94 mm |
| April | -0.4 °C | 13.9 °C | 30.48 mm |
| May | 3.8 °C | 19.1 °C | 44.2 mm |
| June | 7.4 °C | 24 °C | 31.24 mm |
| July | 10.5 °C | 29.8 °C | 13.72 mm |
| August | 9.4 °C | 29.4 °C | 16.26 mm |
| September | 5.3 °C | 23.6 °C | 25.91 mm |
| October | -0.2 °C | 15.4 °C | 29.72 mm |
| November | -5.3 °C | 6.3 °C | 22.35 mm |
| December | -10.1 °C | -0.8 °C | 25.15 mm |
| Annual | -0.3 °C | 14.1 °C | 316.76 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| 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 | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |