Current Sea Water Temperature:
+69.8°F
| Maximum Sea Water Temperature in August: | 74.6°F |
| Minimum Sea Water Temperature in August: | 60.8°F |
| Average water temperature in August: | 67.0°F |
| detailed information | |
Sea Water Temperature for the Last 10 Days:
| August 25 | 69.8°F | August 20 | 69.8°F |
| August 24 | 67.2°F | August 19 | 69.4°F |
| August 23 | 67.6°F | August 18 | 70.2°F |
| August 22 | 67.2°F | August 17 | 68.0°F |
| August 21 | 67.4°F | August 16 | 69.6°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
The average sea surface temperature in August 2026 for Portsmouth was 69.0°F. The maximum and minimum values were 66.0°F and 74.6°F respectively.
Sea Water Temperature in July
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
The average sea surface temperature in September 2025 for Portsmouth was 62.4°F. The maximum and minimum values were 58.4°F and 64.8°F respectively.
USA Resorts:
NAME
F°
| Boston |  |
+80 |
| Chicago |  |
+80 |
| Hawaii |  |
+84 |
| Houston | |
+106 |
| Las Vegas |  |
+116 |
| Los Angeles | |
+96 |
| Maui | |
+70 |
| Miami | |
+92 |
| Myrtle Beach | |
+84 |
| New York | |
+82 |
| San Diego | |
+96 |
| San Francisco | |
+64 |
| Santa Monica | |
+86 |
| Sarasota | |
+92 |
| Washington | |
+84 |
Countries:
NAME
POPULARITY
24 Hours Weather Forecast
Portsmouth
Local time: 17:38
25 aug, tuesday
| 1800 |  |
86°F | E 7 mph |
| 2100 |  |
74°F | E 7 mph |
26 aug, wednesday
| 0000 | |
68°F | E 7 mph |
| 0300 | |
62°F | SE 7 mph |
| 0600 | |
60°F | SE 7 mph |
| 0900 | |
68°F | SE 6 mph |
| 1200 | |
76°F | SW 1 mph |
| 1500 |  |
76°F | NW 11 mph |