Measurements:
°C
°F
Grand Marais
74°F
SE 4 mph
Feels like: 78°F
Precip: 1%
World Resorts USA Grand Marais Weather

Grand Marais Sea Water Temperature

Current Sea Water Temperature:
+38.6°F
Maximum Sea Water Temperature in July: 69.6°F
Minimum Sea Water Temperature in July: 34.8°F
Average water temperature in July: 51.4°F

Sea Water Temperature for the Last 10 Days:

July 15 38.6°F July 10 40.0°F
July 14 45.6°F July 09 41.4°F
July 13 45.6°F July 08 40.6°F
July 12 41.8°F July 07 39.6°F
July 11 41.0°F July 06 37.6°F

When is the Warmest Sea for Grand Marais?

According to our data for the last three years for Grand Marais the highest average sea water temperature was in August, September and October.

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 Grand Marais was 62.5°F. The maximum and minimum values were 56.6°F and 67.4°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Grand Marais was 59.5°F. The maximum and minimum values were 55.6°F and 64.2°F respectively.

Sea Water Temperature in October

Select Year: 2025 2024 2023

The average sea surface temperature in October 2025 for Grand Marais was 54.2°F. The maximum and minimum values were 49.6°F and 61.4°F respectively.

Best Time to Visit Grand Marais
The most sunny months:
September 14 days
August 13 days
July 12 days
The most warm months:
August 70.1 °F
July 69.0 °F
September 63.5 °F
Warmest sea temperature:
August 61.3 °F
September 60.2 °F
October 53.1 °F
The most cold months:
January 15.2 °F
February 16.3 °F
December 22.1 °F
The most rainy months:
August 3 days
April 2 days
June 2 days
The most windy months:
November 10 mph
December 9 mph
January 9 mph

Grand Marais 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
Grand Marais
Local time: 15:50
15 jul, wednesday
1800 74°F
SE
7 mph
2100 72°F
SE
6 mph
16 jul, thursday
0000 74°F
SE
9 mph
0300 64°F
SE
5 mph
0600 62°F
S
4 mph
0900 66°F
S
4 mph
1200 72°F
N
4 mph
1500 70°F
NE
3 mph