Allendale, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4 °C (low) to 13.5 °C (high). Annual precipitation averages 998.7 Millimeters. Allendale 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.9 °C | -1 °C | 75.95 mm |
| February | -7.7 °C | 0.3 °C | 56.39 mm |
| March | -3.7 °C | 5.9 °C | 59.94 mm |
| April | 2.2 °C | 12.7 °C | 97.79 mm |
| May | 8.4 °C | 19.3 °C | 105.66 mm |
| June | 13.7 °C | 24.6 °C | 96.77 mm |
| July | 15.8 °C | 26.6 °C | 84.58 mm |
| August | 15.2 °C | 25.9 °C | 87.38 mm |
| September | 11.1 °C | 22.5 °C | 84.33 mm |
| October | 5.2 °C | 15.1 °C | 99.06 mm |
| November | 0 °C | 7.9 °C | 81.79 mm |
| December | -4.4 °C | 1.8 °C | 69.09 mm |
| Annual | 4 °C | 13.5 °C | 998.73 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |