| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F |
| 1990 Hardiness Zone: | Zone 6a: -10F to -5F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | May 1 - May 10 |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers |
| Ecoregion: | 57b - Oak Openings |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 48174 - Romulus, MI | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 17 | 19 | 28 | 37 | 48 | 58 | 62 | 61 | 53 | 41 | 32 | 23 | 40 |
| Avg Max Temp (°F) | 31 | 34 | 45 | 58 | 70 | 79 | 83 | 81 | 74 | 62 | 48 | 36 | 59 |
| Avg Precip (In.) | 1.89 | 1.81 | 2.52 | 3.11 | 3.07 | 3.5 | 3.12 | 3.22 | 3.3 | 2.32 | 2.74 | 2.51 | 33.1 |