American Falls, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 1.1 °C (low) to 15.9 °C (high). Annual precipitation averages 283.7 Millimeters. American Falls is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.3 °C | 1.2 °C | 26.42 mm |
| February | -6.6 °C | 3.9 °C | 18.54 mm |
| March | -2.5 °C | 10.2 °C | 29.97 mm |
| April | 0.3 °C | 15.2 °C | 33.78 mm |
| May | 4.6 °C | 20.6 °C | 35.05 mm |
| June | 8.2 °C | 25.7 °C | 25.65 mm |
| July | 11.7 °C | 31.6 °C | 8.64 mm |
| August | 10.8 °C | 30.8 °C | 13.21 mm |
| September | 6.2 °C | 25.2 °C | 20.32 mm |
| October | 0.8 °C | 16.8 °C | 24.38 mm |
| November | -4.2 °C | 8.1 °C | 22.61 mm |
| December | -7.9 °C | 1.6 °C | 25.15 mm |
| Annual | 1.1 °C | 15.9 °C | 283.72 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |