American Falls, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 34 °F (low) to 60.6 °F (high). Annual precipitation averages 11.2 Inches. 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 | 17.0 °F | 34.1 °F | 1.04 in. |
| February | 20.1 °F | 39.1 °F | 0.73 in. |
| March | 27.5 °F | 50.4 °F | 1.18 in. |
| April | 32.6 °F | 59.4 °F | 1.33 in. |
| May | 40.2 °F | 69.0 °F | 1.38 in. |
| June | 46.7 °F | 78.3 °F | 1.01 in. |
| July | 53.0 °F | 88.8 °F | 0.34 in. |
| August | 51.5 °F | 87.5 °F | 0.52 in. |
| September | 43.1 °F | 77.3 °F | 0.8 in. |
| October | 33.5 °F | 62.3 °F | 0.96 in. |
| November | 24.5 °F | 46.5 °F | 0.89 in. |
| December | 17.7 °F | 34.9 °F | 0.99 in. |
| Annual | 34 °F | 60.6 °F | 11.17 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |