Iona, Idaho has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 31.3 °F (low) to 57 °F (high). Annual precipitation averages 12.2 Inches. Iona 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 | 12.0 °F | 29.0 °F | 1.1 in. |
| February | 15.3 °F | 33.8 °F | 0.76 in. |
| March | 24.8 °F | 46.5 °F | 1.02 in. |
| April | 30.9 °F | 56.9 °F | 1.2 in. |
| May | 38.7 °F | 66.1 °F | 1.75 in. |
| June | 45.1 °F | 74.9 °F | 1.21 in. |
| July | 50.8 °F | 85.2 °F | 0.56 in. |
| August | 48.8 °F | 84.8 °F | 0.65 in. |
| September | 41.3 °F | 74.3 °F | 1.0 in. |
| October | 31.6 °F | 59.6 °F | 1.11 in. |
| November | 22.2 °F | 43.0 °F | 0.85 in. |
| December | 13.6 °F | 30.4 °F | 0.97 in. |
| Annual | 31.3 °F | 57 °F | 12.18 in. |
| 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 : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |