Union City, Michigan has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.7 °F (low) to 57.9 °F (high). Annual precipitation averages 39.6 Inches. Union City is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.1 °F | 30.9 °F | 2.54 in. |
| February | 18.0 °F | 33.7 °F | 2.17 in. |
| March | 26.3 °F | 44.4 °F | 2.38 in. |
| April | 37.4 °F | 57.7 °F | 3.48 in. |
| May | 49.3 °F | 69.2 °F | 4.36 in. |
| June | 58.6 °F | 78.4 °F | 4.4 in. |
| July | 61.6 °F | 82.0 °F | 3.83 in. |
| August | 59.8 °F | 79.9 °F | 4.03 in. |
| September | 52.3 °F | 74.0 °F | 3.45 in. |
| October | 41.3 °F | 61.0 °F | 3.69 in. |
| November | 31.7 °F | 47.4 °F | 2.92 in. |
| December | 23.1 °F | 35.7 °F | 2.37 in. |
| Annual | 39.7 °F | 57.9 °F | 39.62 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |