Current Sea Water Temperature:
+66.4°F
| Maximum Sea Water Temperature in August: | 73.4°F |
| Minimum Sea Water Temperature in August: | 60.8°F |
| Average water temperature in August: | 66.7°F |
| detailed information | |
Sea Water Temperature for the Last 10 Days:
| August 05 | 66.4°F | July 31 | 69.2°F |
| August 04 | 68.2°F | July 30 | 69.0°F |
| August 03 | 68.6°F | July 29 | 66.8°F |
| August 02 | 67.8°F | July 28 | 66.4°F |
| August 01 | 69.8°F | July 27 | 66.4°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 2025 for Portsmouth was 64.8°F. The maximum and minimum values were 60.8°F and 67.0°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 |  |
+94 |
| Chicago | |
+82 |
| Hawaii |  |
+82 |
| Houston | |
+106 |
| Las Vegas | |
+124 |
| Los Angeles | |
+92 |
| Maui | |
+78 |
| Miami | |
+92 |
| Myrtle Beach |  |
+84 |
| New York | |
+84 |
| San Diego | |
+80 |
| San Francisco | |
+62 |
| Santa Monica | |
+80 |
| Sarasota | |
+92 |
| Washington | |
+88 |
Countries:
NAME
POPULARITY
24 Hours Weather Forecast
Portsmouth
Local time: 15:18
05 aug, wednesday
| 1800 |  |
92°F | N 6 mph |
| 2100 |  |
80°F | NE 4 mph |
06 aug, thursday
| 0000 | |
76°F | NE 7 mph |
| 0300 |  |
72°F | NE 6 mph |
| 0600 |  |
70°F | E 5 mph |
| 0900 | |
82°F | E 4 mph |
| 1200 | |
90°F | NE 2 mph |
| 1500 | |
88°F | NW 6 mph |