Iona, Minnesota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 34.8 °F (low) to 54.1 °F (high). Annual precipitation averages 30.1 Inches. Iona is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.2 °F | 23.0 °F | 0.77 in. |
| February | 10.1 °F | 27.4 °F | 0.92 in. |
| March | 21.3 °F | 39.4 °F | 1.54 in. |
| April | 33.4 °F | 54.5 °F | 3.07 in. |
| May | 46.3 °F | 67.5 °F | 3.88 in. |
| June | 57.7 °F | 77.8 °F | 4.65 in. |
| July | 61.2 °F | 81.6 °F | 3.56 in. |
| August | 58.5 °F | 78.9 °F | 3.46 in. |
| September | 49.9 °F | 72.2 °F | 3.5 in. |
| October | 36.6 °F | 58.1 °F | 2.32 in. |
| November | 23.6 °F | 41.5 °F | 1.32 in. |
| December | 12.2 °F | 27.7 °F | 1.11 in. |
| Annual | 34.8 °F | 54.1 °F | 30.1 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |