Wellston, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.9 °C (low) to 13.3 °C (high). Annual precipitation averages 937.8 Millimeters. Wellston 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 | -9.7 °C | -1.7 °C | 63.5 mm |
| February | -9.8 °C | -0.1 °C | 49.02 mm |
| March | -6.2 °C | 5.4 °C | 58.17 mm |
| April | -0.2 °C | 12.9 °C | 88.14 mm |
| May | 6 °C | 20.2 °C | 92.2 mm |
| June | 11.3 °C | 25.1 °C | 88.65 mm |
| July | 13.4 °C | 27.2 °C | 83.31 mm |
| August | 12.8 °C | 26.1 °C | 75.69 mm |
| September | 9.1 °C | 22.2 °C | 83.57 mm |
| October | 3.2 °C | 14.6 °C | 105.41 mm |
| November | -1.6 °C | 6.9 °C | 82.04 mm |
| December | -6.1 °C | 1.1 °C | 68.07 mm |
| Annual | 1.9 °C | 13.3 °C | 937.77 mm |
| 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 : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |