Brown City, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.8 °C (low) to 13.7 °C (high). Annual precipitation averages 819.9 Millimeters. Brown City is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.4 °C | -1.3 °C | 54.1 mm |
| February | -9.5 °C | 0.2 °C | 43.69 mm |
| March | -4.8 °C | 5.6 °C | 48.26 mm |
| April | 0.9 °C | 12.9 °C | 79.5 mm |
| May | 7.1 °C | 19.7 °C | 87.38 mm |
| June | 12.5 °C | 25.4 °C | 82.55 mm |
| July | 14.8 °C | 27.6 °C | 86.11 mm |
| August | 14.1 °C | 26.3 °C | 76.71 mm |
| September | 10 °C | 23.1 °C | 75.69 mm |
| October | 4.5 °C | 15.7 °C | 71.88 mm |
| November | -1.1 °C | 8.1 °C | 62.99 mm |
| December | -5.7 °C | 1.6 °C | 51.05 mm |
| Annual | 2.8 °C | 13.7 °C | 819.91 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |