| 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. 21 - Oct. 31 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 57a - Maumee Lake Plains |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 48079 - Saint Clair, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 16 | 17 | 25 | 36 | 47 | 57 | 62 | 61 | 53 | 42 | 32 | 22 | 39 |
| Avg Max Temp (°F) | 30 | 33 | 42 | 54 | 67 | 77 | 82 | 80 | 73 | 60 | 47 | 36 | 57 |
| Avg Precip (In.) | 1.81 | 1.59 | 2.27 | 2.98 | 2.77 | 3.2 | 3.01 | 3.09 | 3.4 | 2.42 | 2.76 | 2.23 | 31.54 |