World Resorts USA Grand Marais Weather

Grand Marais sea water temperature

Current sea water temperature:
+38.3°F
Minimum sea water temperature in December: 43.9°F
Maximum sea water temperature in December: 37.0°F
Average sea water temperature in December: 39.5°F

Sea water temperature for the last 10 days:

December 24 38.3°F December 19 38.7°F
December 23 37.0°F December 18 38.7°F
December 22 37.9°F December 17 39.2°F
December 21 39.2°F December 16 38.1°F
December 20 37.8°F December 15 37.8°F

When is the warmest sea in Grand Marais?

Based on the data about daily sea water temperature for the last three years the warmest sea in Grand Marais was noticed in August, September and October.

Monthly Sea Temperatures in Grand Marais, °F

Sea water temperature in August, °F

Show year:
2025
2024
2023

The average sea water temperature in August of 2025 was 61.3°F. The highest and lowest sea temperatures during the month were 65.7°F and 55.9°F.

Sea water temperature in September, °F

Show year:
2025
2024
2023

The average sea water temperature in September of 2025 was 58.5°F. The highest and lowest sea temperatures during the month were 62.8°F and 55.0°F.

Sea water temperature in October, °F

Show year:
2025
2024
2023

The average sea water temperature in October of 2025 was 53.8°F. The highest and lowest sea temperatures during the month were 60.3°F and 49.6°F.

Best time for vacation in Grand Marais

Sunniest months:
September 14 days
August 13 days
July 12 days
Warmest months:
August 68.1 °F
July 67.1 °F
September 62.2 °F
Warmest sea temp:
August 60.2 °F
September 59.1 °F
October 52.8 °F
Coldest months:
February 18.9 °F
January 19.4 °F
December 25.9 °F
Rainiest months:
August 3 days
April 2 days
July 2 days
Windiest months:
November 10.0 mph
December 9.8 mph
April 9.6 mph

Grand Marais on a weather map

Grand Marais
+28°F
NW 2 mph
Feels like: +21°F
Precip.: 0%
Places in USA:
Name
°F
+43°F
+73°F
+73°F
+50°F
+61°F
+70°F
+75°F
+64°F
+37°F
+61°F
+55°F
+61°F
+61°F
+68°F
+36°F
24 Hours Forecast
Grand Marais
Local time: 07:37
December 24, wednesday
0900
28°F
NW
2 mph
1200
32°F
N
4 mph
1500
34°F
NE
5 mph
1800
30°F
SE
4 mph
2100
28°F
S
7 mph
December 25, thursday
0000
21°F
S
7 mph
0300
18°F
S
7 mph
0600
16°F
SW
6 mph
Units of measurement: °C / °F