Measurements:
°C
°F
Portsmouth
52°F
SE 19 mph
Feels like: 46°F
Precip: 2%
World Resorts USA Portsmouth Weather

Portsmouth Sea Water Temperature

Current Sea Water Temperature:
+60.6°F
Maximum Sea Water Temperature in October: 64.6°F
Minimum Sea Water Temperature in October: 53.2°F
Average water temperature in October: 58.3°F

Sea Water Temperature for the Last 10 Days:

October 05 60.6°F September 30 60.6°F
October 04 61.8°F September 29 60.6°F
October 03 62.0°F September 28 61.8°F
October 02 61.8°F September 27 61.6°F
October 01 61.4°F September 26 61.8°F

When is the Warmest Sea for Portsmouth?

According to our data for the last three years for Portsmouth 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 Portsmouth was 69.1°F. The maximum and minimum values were 66.0°F and 74.6°F respectively.

Sea Water Temperature in July

Select Year: 2026 2025 2024

The average sea surface temperature in July 2026 for Portsmouth was 67.5°F. The maximum and minimum values were 64.4°F and 72.4°F respectively.

Sea Water Temperature in September

Select Year: 2026 2025 2024

The average sea surface temperature in September 2026 for Portsmouth was 65.3°F. The maximum and minimum values were 60.6°F and 69.2°F respectively.

Best Time to Visit Portsmouth
The most sunny months:
November 16 days
October 14 days
July 13 days
The most warm months:
July 82.8 °F
August 80.9 °F
June 76.1 °F
Warmest sea temperature:
August 67.0 °F
July 65.2 °F
September 63.8 °F
The most cold months:
January 30.9 °F
February 32.1 °F
December 36.4 °F
The most rainy months:
July 3 days
August 2 days
September 2 days
The most windy months:
January 9 mph
March 9 mph
November 9 mph

Portsmouth on the Weather Map

USA Resorts:
NAME
F°
Boston +58
Chicago +62
Hawaii +82
Houston +86
Las Vegas +92
Los Angeles +100
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
Portsmouth
Local time: 19:52
05 oct, monday
2100 52°F
SE
19 mph
06 oct, tuesday
0000 46°F
SE
17 mph
0300 44°F
E
17 mph
0600 42°F
E
19 mph
0900 44°F
SE
19 mph
1200 52°F
SE
20 mph
1500 58°F
SE
18 mph
1800 54°F
SE
13 mph