Measurements:
°C
°F
Mackinac Island
50°F
S 13 mph
Feels like: 44°F
Precip: 3%
World Resorts USA Mackinac Island Weather

Mackinac Island Sea Water Temperature

Current Sea Water Temperature:
+59.6°F
Maximum Sea Water Temperature in October: 66.0°F
Minimum Sea Water Temperature in October: 46.4°F
Average water temperature in October: 56.7°F

Sea Water Temperature for the Last 10 Days:

October 05 59.6°F September 30 60.8°F
October 04 61.4°F September 29 60.8°F
October 03 61.6°F September 28 59.6°F
October 02 61.2°F September 27 59.2°F
October 01 60.0°F September 26 58.4°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 64.2°F. The maximum and minimum values were 58.4°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 64.5 °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
July 2 days
April 2 days
The most windy months:
November 13 mph
December 13 mph
April 11 mph

Mackinac Island on the Weather Map

USA Resorts:
NAME
F°
Boston +58
Chicago +60
Hawaii +82
Houston +84
Las Vegas +92
Los Angeles +102
Maui +74
Miami +88
Myrtle Beach +70
New York +62
San Diego +84
San Francisco +66
Santa Monica +94
Sarasota +84
Washington +64
24 Hours Weather Forecast
Mackinac Island
Local time: 21:04
06 oct, tuesday
0000 48°F
S
4 mph
0300 46°F
N
6 mph
0600 46°F
N
10 mph
0900 46°F
N
11 mph
1200 54°F
N
12 mph
1500 64°F
N
14 mph
1800 66°F
NE
13 mph
2100 64°F
NE
19 mph