Current Sea Water Temperature:
+47.4°F
| Maximum Sea Water Temperature in May: | 55.8°F |
| Minimum Sea Water Temperature in May: | 42.4°F |
| Average water temperature in May: | 49.2°F |
| detailed information | |
Sea Water Temperature for the Last 10 Days:
| May 14 | 47.4°F | May 09 | 45.8°F |
| May 13 | 46.8°F | May 08 | 46.4°F |
| May 12 | 47.2°F | May 07 | 47.4°F |
| May 11 | 47.0°F | May 06 | 47.6°F |
| May 10 | 45.2°F | May 05 | 47.0°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 2025 for Portsmouth was 64.5°F. The maximum and minimum values were 61.8°F and 69.8°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 |  |
+62 |
| Chicago |  |
+56 |
| Hawaii |  |
+76 |
| Honolulu | |
+76 |
| Houston | |
+94 |
| Las Vegas | |
+88 |
| Los Angeles | |
+66 |
| Maui | |
+70 |
| Miami | |
+94 |
| Miami Beach | |
+90 |
| New York | |
+68 |
| San Diego | |
+66 |
| San Francisco | |
+62 |
| Sarasota | |
+94 |
| Tampa | |
+94 |
Countries:
NAME
POPULARITY
24 Hours Weather Forecast
Portsmouth
Local time: 12:15
14 may, thursday
| 1500 |  |
56°F | NW 11 mph |
| 1800 |  |
54°F | W 10 mph |
| 2100 | |
52°F | W 9 mph |
15 may, friday
| 0000 |  |
50°F | W 14 mph |
| 0300 | |
48°F | W 12 mph |
| 0600 | |
48°F | W 9 mph |
| 0900 | |
48°F | SW 11 mph |
| 1200 | |
48°F | SW 13 mph |