Current sea water temperature:
+42.1°F
| Minimum sea water temperature in December: | 50.7°F |
| Maximum sea water temperature in December: | 41.9°F |
| Average sea water temperature in December: | 45.7°F |
| more information | |
14 days
forecast
forecast
| Portsmouth |
monthly
weather
weather
| Portsmouth |
Sea water temperature for the last 10 days:
| December 31 | 42.1°F | December 26 | 43.5°F |
| December 30 | 42.3°F | December 25 | 43.7°F |
| December 29 | 42.4°F | December 24 | 43.5°F |
| December 28 | 42.4°F | December 23 | 43.5°F |
| December 27 | 43.2°F | December 22 | 43.7°F |
Monthly sea water temperature, °F
When is the warmest sea in Portsmouth?
Based on the data about daily sea water temperature for the last three years the warmest sea in Portsmouth was noticed in August, July and September.
Monthly Sea Temperatures in Portsmouth, °F
Sea water temperature in August, °F
Show year:
2025
2024
2023
The average sea water temperature in August of 2025 was 63.3°F. The highest and lowest sea temperatures during the month were 65.3°F and 59.7°F.
Sea water temperature in July, °F
Show year:
2025
2024
2023
The average sea water temperature in July of 2025 was 63.1°F. The highest and lowest sea temperatures during the month were 67.8°F and 60.6°F.
Sea water temperature in September, °F
Show year:
2025
2024
2023
The average sea water temperature in September of 2025 was 61.1°F. The highest and lowest sea temperatures during the month were 63.3°F and 57.6°F.
current
weather
weather
| Portsmouth |
weather in
January
January
| Portsmouth |
Best time for vacation in Portsmouth
Portsmouth on a weather map
Places in USA:
Name
°F
24 Hours Forecast
Portsmouth
Local time: 10:13
December 31, wednesday
1200
27°F
NE
14 mph
14 mph
1500
28°F
NE
12 mph
12 mph
1800
28°F
NE
10 mph
10 mph
2100
27°F
NE
10 mph
10 mph
January 01, thursday
0000
27°F
NE
11 mph
11 mph
0300
27°F
N
11 mph
11 mph
0600
25°F
NE
10 mph
10 mph
0900
25°F
E
12 mph
12 mph
