Measurements:
°C
°F
Mackinac Island
62°F
N 19 mph
Feels like: 62°F
Precip: 31%
World Resorts USA Mackinac Island Weather

Mackinac Island Sea Water Temperature

Current Sea Water Temperature:
+65.4°F
Maximum Sea Water Temperature in September: 71.0°F
Minimum Sea Water Temperature in September: 56.6°F
Average water temperature in September: 64.3°F

Sea Water Temperature for the Last 10 Days:

September 15 65.4°F September 10 67.6°F
September 14 66.4°F September 09 69.2°F
September 13 67.0°F September 08 68.2°F
September 12 68.0°F September 07 67.8°F
September 11 67.6°F September 06 67.6°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: 2026 2025 2024

The average sea surface temperature in August 2026 for Mackinac Island was 70.4°F. The maximum and minimum values were 65.4°F and 73.8°F respectively.

Sea Water Temperature in July

Select Year: 2026 2025 2024

The average sea surface temperature in July 2026 for Mackinac Island was 68.7°F. The maximum and minimum values were 63.6°F and 73.2°F respectively.

Sea Water Temperature in September

Select Year: 2026 2025 2024

The average sea surface temperature in September 2026 for Mackinac Island was 67.0°F. The maximum and minimum values were 64.8°F and 69.2°F respectively.

Best Time to Visit Mackinac Island
The most sunny months:
July 16 days
August 14 days
June 12 days
The most warm months:
August 71.7 °F
July 71.6 °F
September 64.4 °F
Warmest sea temperature:
August 69.4 °F
July 67.0 °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 +64
Chicago +66
Hawaii +80
Las Vegas +80
Los Angeles +74
Maui +66
Miami +92
Myrtle Beach +86
New York +72
Panama City Beach +90
San Diego +72
San Francisco +60
Santa Monica +72
Sarasota +94
Washington +76
24 Hours Weather Forecast
Mackinac Island
Local time: 10:35
15 sep, tuesday
1200 62°F
N
19 mph
1500 66°F
NE
21 mph
1800 72°F
NE
19 mph
2100 62°F
SE
14 mph
16 sep, wednesday
0000 60°F
SE
12 mph
0300 60°F
SE
12 mph
0600 58°F
SE
9 mph
0900 58°F
SE
4 mph