‹ Mackinac Island weather by month
Typical September weather
Mackinac Island
Michigan · September
70° days
45° nights
about 8 rainy days · 12½ hours of daylight · lake 64°
What to pack
- Sweater
- Umbrella
What September feels like
The Labor Day bridge walk over on the mainland marks the turn: after it, ferry queues shorten and the island relaxes without closing anything. Color starts showing in the hardwoods late in the month and the light over the straits gets genuinely beautiful.
Rain arrives about 8 days of the month, so keep one flexible day in your plans. Humidity stays comfortable; the air never feels heavy.
Can you swim?
The lake runs about 64° — cold — a quick dip takes resolve.
The numbers
| Typical high | 70° |
|---|---|
| Typical low | 45° |
| Days with real rain | 8 |
| Total rain | 3.4 in |
| Humidity | comfortable |
| Water temperature | 64° |
| Sunrise / sunset (mid-month) | 7:17 am / 7:50 pm |