| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F | |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F | |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F | |
| Average First Frost Date: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 56b - Elkhart Till Plains | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 49130 - Union, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 15 | 18 | 27 | 37 | 48 | 57 | 61 | 59 | 52 | 41 | 32 | 21 | 39 |
| Avg Max Temp (°F) | 31 | 35 | 46 | 59 | 71 | 80 | 84 | 81 | 74 | 62 | 48 | 36 | 59 |
| Avg Precip (In.) | 2.02 | 1.74 | 2.65 | 3.44 | 3.58 | 3.92 | 3.69 | 3.84 | 3.65 | 3.05 | 3.05 | 2.76 | 37.39 |