Alanson, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1 °C (low) to 12.1 °C (high). Annual precipitation averages 859 Millimeters. Alanson is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.4 °C | -2.7 °C | 59.94 mm |
| February | -12.3 °C | -1.6 °C | 39.37 mm |
| March | -8.2 °C | 3.8 °C | 46.23 mm |
| April | -1.2 °C | 10.6 °C | 72.9 mm |
| May | 5.2 °C | 18.4 °C | 74.42 mm |
| June | 10.6 °C | 23.7 °C | 73.15 mm |
| July | 13.3 °C | 25.9 °C | 70.87 mm |
| August | 12.6 °C | 25.3 °C | 80.01 mm |
| September | 8.6 °C | 21.3 °C | 89.41 mm |
| October | 3.2 °C | 13.7 °C | 107.95 mm |
| November | -1.6 °C | 6.5 °C | 77.22 mm |
| December | -6.6 °C | 0.6 °C | 67.56 mm |
| Annual | 1 °C | 12.1 °C | 859.03 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |