Measurements:
°C
°F
Mackinac Island
-2°F
SW 4 mph
Feels like: -16°F
Precip: 0%
World Resorts USA Mackinac Island Weather

Mackinac Island Sea Water Temperature

Current Sea Water Temperature:
+30.2°F
Maximum Sea Water Temperature in January: 37.2°F
Minimum Sea Water Temperature in January: 30.0°F
Average water temperature in January: 33.7°F

Sea Water Temperature for the Last 10 Days:

January 29 30.2°F January 24 30.4°F
January 28 30.2°F January 23 30.4°F
January 27 30.2°F January 22 30.6°F
January 26 30.0°F January 21 31.0°F
January 25 30.4°F January 20 31.2°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
September 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 19.9 °F
January 20.5 °F
December 28.6 °F
The most rainy months:
August 3 days
May 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
Chicago +12
Hawaii +80
Honolulu +80
Houston +62
Las Vegas +66
Los Angeles +76
Maui +74
Miami +70
Miami Beach +74
New York +18
San Diego +80
San Francisco +58
Sarasota +68
Tampa +70
Washington +18
24 Hours Weather Forecast
Mackinac Island
Local time: 14:09
29 jan, thursday
1500 -2°F
SW
4 mph
1800 0°F
SW
4 mph
2100 -4°F
S
4 mph
30 jan, friday
0000 -8°F
SW
6 mph
0300 -14°F
S
6 mph
0600 -16°F
S
4 mph
0900 -14°F
SE
5 mph
1200 -6°F
SE
9 mph