Measurements:
°C
°F
Boston
30°F
E 6 mph
Feels like: 22°F
Precip: 0%
World Resorts USA Boston Weather

Boston Sea Water Temperature

Current Sea Water Temperature:
+41.2°F
Maximum Sea Water Temperature in December: 50.2°F
Minimum Sea Water Temperature in December: 36.6°F
Average water temperature in December: 44.4°F

Sea Water Temperature for the Last 10 Days:

December 18 41.2°F December 13 42.6°F
December 17 41.6°F December 12 43.0°F
December 16 41.6°F December 11 43.6°F
December 15 42.8°F December 10 43.4°F
December 14 42.6°F December 09 43.0°F

When is the Warmest Sea for Boston?

According to our data for the last three years for Boston 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 Boston was 69.2°F. The maximum and minimum values were 66.6°F and 72.8°F respectively.

Sea Water Temperature in July

Select Year: 2025 2024 2023

The average sea surface temperature in July 2025 for Boston was 69.0°F. The maximum and minimum values were 65.2°F and 72.2°F respectively.

Sea Water Temperature in September

Select Year: 2025 2024 2023

The average sea surface temperature in September 2025 for Boston was 65.3°F. The maximum and minimum values were 61.2°F and 68.6°F respectively.

Best Time to Visit Boston
The most sunny months:
August 16 days
July 15 days
November 14 days
The most warm months:
July 85.5 °F
August 83.7 °F
June 76.9 °F
Warmest sea temperature:
August 69.5 °F
July 68.6 °F
September 65.9 °F
The most cold months:
January 31.5 °F
February 33.1 °F
December 38.2 °F
The most rainy months:
April 5 days
May 4 days
October 4 days
The most windy months:
January 11 mph
March 11 mph
February 10 mph

Boston on the Weather Map

USA Resorts:
NAME
Chicago +38
Hawaii +76
Honolulu +76
Houston +64
Las Vegas +50
Los Angeles +54
Maui +72
Miami +72
Miami Beach +78
New York +30
San Diego +52
San Francisco +50
Sarasota +64
Tampa +62
Washington +30
24 Hours Weather Forecast
Boston
Local time: 04:16
18 dec, thursday
0600 24°F
NE
5 mph
0900 28°F
N
4 mph
1200 38°F
N
5 mph
1500 42°F
N
8 mph
1800 38°F
N
8 mph
2100 40°F
N
9 mph
19 dec, friday
0000 44°F
N
11 mph
0300 48°F
N
12 mph