Chatham, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.4 °F (low) to 51.6 °F (high). Annual precipitation averages 36 Inches. Chatham is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.7 °F | 24.6 °F | 2.36 in. |
| February | 7.3 °F | 27.5 °F | 1.76 in. |
| March | 15.7 °F | 36.8 °F | 1.79 in. |
| April | 27.6 °F | 48.3 °F | 2.47 in. |
| May | 39.4 °F | 62.5 °F | 3.18 in. |
| June | 48.7 °F | 72.9 °F | 3.34 in. |
| July | 54.1 °F | 77.2 °F | 3.53 in. |
| August | 53.0 °F | 76.1 °F | 3.03 in. |
| September | 46.2 °F | 68.4 °F | 4.19 in. |
| October | 35.5 °F | 54.3 °F | 4.69 in. |
| November | 25.7 °F | 40.6 °F | 3.08 in. |
| December | 15.4 °F | 29.7 °F | 2.6 in. |
| Annual | 31.4 °F | 51.6 °F | 36.02 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |