Amasa, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2 °C (low) to 10.5 °C (high). Annual precipitation averages 739.1 Millimeters. Amasa is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16.3 °C | -5.7 °C | 33.78 mm |
| February | -16.2 °C | -3.4 °C | 26.92 mm |
| March | -11.1 °C | 2.8 °C | 36.32 mm |
| April | -3.6 °C | 9.7 °C | 64.26 mm |
| May | 3.6 °C | 18 °C | 76.96 mm |
| June | 9.1 °C | 23.2 °C | 83.57 mm |
| July | 11.3 °C | 25.4 °C | 86.11 mm |
| August | 10.2 °C | 24.2 °C | 76.2 mm |
| September | 6.4 °C | 19.8 °C | 89.15 mm |
| October | 0.4 °C | 11.8 °C | 80.52 mm |
| November | -5.4 °C | 3.6 °C | 46.23 mm |
| December | -12.1 °C | -3.1 °C | 39.12 mm |
| Annual | -2 °C | 10.5 °C | 739.14 mm |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |