Measurements:
°C
°F
Mackinac Island
68°F
E 9 mph
Feels like: 68°F
Precip: 0%
World Resorts USA Mackinac Island Weather

Mackinac Island Sea Water Temperature

Current Sea Water Temperature:
+48.4°F
Maximum Sea Water Temperature in June: 63.0°F
Minimum Sea Water Temperature in June: 44.4°F
Average water temperature in June: 55.2°F

Sea Water Temperature for the Last 10 Days:

June 04 48.4°F May 29 45.2°F
June 03 47.6°F May 28 46.4°F
June 01 46.8°F May 27 44.4°F
May 31 46.6°F May 26 42.6°F
May 30 44.8°F May 25 42.8°F

When is the Warmest Sea for Mackinac Island?

According to our data for the last three years for Mackinac Island the highest average sea water temperature was in August, July and September.

Average Water Temperature by Month, °F

Sea Water Temperature in August

Select Year: 2025 2024 2023

The average sea surface temperature in August 2025 for Mackinac Island was 71.6°F. The maximum and minimum values were 67.0°F and 74.8°F respectively.

Sea Water Temperature in July

Select Year: 2025 2024 2023

The average sea surface temperature in July 2025 for Mackinac Island was 67.6°F. The maximum and minimum values were 60.0°F and 73.0°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Mackinac Island was 63.3°F. The maximum and minimum values were 60.4°F and 69.0°F respectively.

Best Time to Visit Mackinac Island
The most sunny months:
July 14 days
August 14 days
May 12 days
The most warm months:
August 71.6 °F
July 71.5 °F
September 64.4 °F
Warmest sea temperature:
August 69.2 °F
July 66.8 °F
September 64.1 °F
The most cold months:
February 20.1 °F
January 20.4 °F
December 28.6 °F
The most rainy months:
August 3 days
April 2 days
July 2 days
The most windy months:
November 13 mph
December 13 mph
April 11 mph

Mackinac Island on the Weather Map

USA Resorts:
NAME
Boston +90
Chicago +76
Hawaii +78
Honolulu +78
Houston +86
Las Vegas +92
Los Angeles +70
Maui +70
Miami +82
Miami Beach +84
New York +94
San Diego +64
San Francisco +60
Sarasota +94
Tampa +92
24 Hours Weather Forecast
Mackinac Island
Local time: 12:54
04 jun, thursday
1500 70°F
E
9 mph
1800 72°F
NE
6 mph
2100 62°F
NW
6 mph
05 jun, friday
0000 60°F
N
7 mph
0300 60°F
NE
7 mph
0600 60°F
NE
9 mph
0900 60°F
NE
12 mph
1200 60°F
N
7 mph