Measurements:
°C
°F
Mackinac Island
80°F
SE 11 mph
Feels like: 82°F
Precip: 2%
World Resorts USA Mackinac Island Weather

Mackinac Island Sea Water Temperature

Current Sea Water Temperature:
+72.6°F
Maximum Sea Water Temperature in July: 74.2°F
Minimum Sea Water Temperature in July: 57.8°F
Average water temperature in July: 66.9°F

Sea Water Temperature for the Last 10 Days:

July 15 72.6°F July 10 70.4°F
July 14 72.4°F July 09 69.0°F
July 13 71.8°F July 08 69.0°F
July 12 71.6°F July 07 68.2°F
July 11 73.2°F July 06 66.8°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: 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: 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
June 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 +96
Chicago +86
Hawaii +82
Houston +80
Las Vegas +118
Los Angeles +100
Maui +78
Miami +96
Myrtle Beach +90
New York +104
San Diego +94
San Francisco +82
Santa Monica +82
Sarasota +96
Tampa +98
24 Hours Weather Forecast
Mackinac Island
Local time: 16:50
15 jul, wednesday
1800 80°F
SE
11 mph
2100 72°F
SE
11 mph
16 jul, thursday
0000 66°F
SE
9 mph
0300 66°F
SE
8 mph
0600 66°F
E
9 mph
0900 70°F
SE
10 mph
1200 78°F
E
9 mph
1500 82°F
E
10 mph