Westphalia, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.3 °F (low) to 57.4 °F (high). Annual precipitation averages 35.4 Inches. Westphalia 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 | 15.7 °F | 29.7 °F | 2.28 in. |
| February | 16.9 °F | 33.1 °F | 2.06 in. |
| March | 25.0 °F | 43.6 °F | 2.19 in. |
| April | 35.1 °F | 56.9 °F | 3.48 in. |
| May | 47.1 °F | 69.1 °F | 3.92 in. |
| June | 56.7 °F | 78.3 °F | 3.61 in. |
| July | 60.3 °F | 82.0 °F | 3.26 in. |
| August | 58.6 °F | 80.1 °F | 3.52 in. |
| September | 50.5 °F | 73.4 °F | 2.97 in. |
| October | 40.0 °F | 60.5 °F | 3.3 in. |
| November | 30.9 °F | 46.7 °F | 2.67 in. |
| December | 22.3 °F | 35.0 °F | 2.12 in. |
| Annual | 38.3 °F | 57.4 °F | 35.38 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 |