Ionia, Michigan has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.7 °F (low) to 57.4 °F (high). Annual precipitation averages 36.7 Inches. Ionia is located in USDA Plant Hardiness Zone 6a. 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 | 16.6 °F | 30.1 °F | 2.38 in. |
| February | 17.3 °F | 33.0 °F | 2.13 in. |
| March | 25.0 °F | 43.5 °F | 2.29 in. |
| April | 35.3 °F | 57.1 °F | 3.7 in. |
| May | 47.0 °F | 68.9 °F | 4.15 in. |
| June | 57.1 °F | 78.4 °F | 3.56 in. |
| July | 60.8 °F | 82.3 °F | 3.39 in. |
| August | 59.2 °F | 80.2 °F | 3.62 in. |
| September | 50.9 °F | 73.0 °F | 3.05 in. |
| October | 40.4 °F | 60.4 °F | 3.32 in. |
| November | 31.2 °F | 46.7 °F | 2.87 in. |
| December | 23.0 °F | 35.3 °F | 2.2 in. |
| Annual | 38.7 °F | 57.4 °F | 36.66 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 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |