| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 1b: -15F to -10F |
| Average First Frost Date: | Oct. 11 - Oct. 20 |
| Average Last Frost Date: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 50ag - Newaygo Barrens |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 49619 - Brethren, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 15 | 22 | 33 | 43 | 52 | 57 | 56 | 49 | 39 | 30 | 20 | 36 |
| Avg Max Temp (°F) | 29 | 32 | 42 | 54 | 68 | 76 | 81 | 78 | 71 | 59 | 45 | 33 | 56 |
| Avg Precip (In.) | 2.24 | 1.51 | 2.11 | 2.67 | 2.87 | 3.24 | 3.06 | 3.79 | 3.86 | 3.4 | 2.93 | 2.35 | 34.03 |