Ironton, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.4 °F (low) to 53.7 °F (high). Annual precipitation averages 33.8 Inches. Ironton is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.2 °F | 27.7 °F | 2.25 in. |
| February | 13.7 °F | 29.3 °F | 1.49 in. |
| March | 20.2 °F | 38.5 °F | 1.78 in. |
| April | 31.7 °F | 51.3 °F | 2.77 in. |
| May | 42.7 °F | 64.5 °F | 3.03 in. |
| June | 52.8 °F | 73.4 °F | 3.0 in. |
| July | 58.1 °F | 77.8 °F | 2.75 in. |
| August | 57.6 °F | 77.1 °F | 3.19 in. |
| September | 50.6 °F | 70.3 °F | 3.66 in. |
| October | 40.1 °F | 56.9 °F | 4.29 in. |
| November | 31.1 °F | 44.0 °F | 2.91 in. |
| December | 22.6 °F | 33.5 °F | 2.67 in. |
| Annual | 36.4 °F | 53.7 °F | 33.79 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |