Current sea water temperature:
+45.3°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: | 45.9°F |
| more information | |
14 days
forecast
forecast
| Portsmouth |
monthly
weather
weather
| Portsmouth |
Sea water temperature for the last 10 days:
| December 14 | 45.3°F | December 9 | 45.9°F |
| December 13 | 45.3°F | December 8 | 46.6°F |
| December 12 | 45.5°F | December 7 | 46.8°F |
| December 11 | 45.9°F | December 6 | 46.8°F |
| December 10 | 46.0°F | December 5 | 46.8°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
December
December
| Portsmouth |
Best time for vacation in Portsmouth
Portsmouth on a weather map
Places in USA:
Name
°F
24 Hours Forecast
Portsmouth
Local time: 21:28
December 15, monday
0000
16°F
SE
11 mph
11 mph
0300
12°F
SE
12 mph
12 mph
0600
12°F
SE
13 mph
13 mph
0900
14°F
SE
15 mph
15 mph
1200
23°F
E
17 mph
17 mph
1500
23°F
SE
14 mph
14 mph
1800
23°F
E
12 mph
12 mph
2100
21°F
E
11 mph
11 mph
