Mason, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.2 °F (low) to 57.1 °F (high). Annual precipitation averages 34.8 Inches. Mason 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 15.8 °F | 30.1 °F | 2.26 in. |
| February | 16.5 °F | 33.0 °F | 1.83 in. |
| March | 24.8 °F | 43.4 °F | 2.19 in. |
| April | 35.8 °F | 56.5 °F | 3.39 in. |
| May | 47.4 °F | 68.4 °F | 3.8 in. |
| June | 56.7 °F | 77.6 °F | 3.73 in. |
| July | 59.8 °F | 81.4 °F | 3.36 in. |
| August | 58.3 °F | 79.5 °F | 3.43 in. |
| September | 50.7 °F | 73.5 °F | 3.06 in. |
| October | 39.8 °F | 60.2 °F | 3.06 in. |
| November | 30.5 °F | 46.8 °F | 2.56 in. |
| December | 22.4 °F | 35.3 °F | 2.09 in. |
| Annual | 38.2 °F | 57.1 °F | 34.76 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°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 |