Current Sea Water Temperature:
+40.6°F
| Maximum Sea Water Temperature in January: | 45.4°F |
| Minimum Sea Water Temperature in January: | 38.2°F |
| Average water temperature in January: | 40.8°F |
| detailed information | |
Sea Water Temperature for the Last 10 Days:
| January 06 | 40.6°F | January 01 | 40.8°F |
| January 05 | 40.8°F | December 31 | 41.2°F |
| January 04 | 41.0°F | December 30 | 41.4°F |
| January 03 | 40.6°F | December 29 | 41.6°F |
| January 02 | 41.4°F | December 28 | 41.6°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 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°
| Chicago |  |
+38 |
| Hawaii | |
+76 |
| Honolulu | |
+76 |
| Houston |  |
+68 |
| Las Vegas | |
+48 |
| Los Angeles | |
+58 |
| Maui | |
+70 |
| Miami | |
+70 |
| Miami Beach | |
+74 |
| New York | |
+38 |
| San Diego | |
+60 |
| San Francisco | |
+52 |
| Sarasota | |
+66 |
| Tampa | |
+64 |
| Washington | |
+40 |
Countries:
NAME
POPULARITY
24 Hours Weather Forecast
Portsmouth
Local time: 00:17
07 jan, wednesday
| 0300 |  |
24°F | SW 9 mph |
| 0600 | |
24°F | SW 9 mph |
| 0900 |  |
28°F | S 7 mph |
| 1200 | |
30°F | S 7 mph |
| 1500 | |
32°F | SE 6 mph |
| 1800 | |
32°F | SE 4 mph |
| 2100 |  |
32°F | SE 4 mph |
08 jan, thursday
| 0000 |  |
30°F | E 7 mph |