Measurements:
°C
°F
CURRENT WEATHER
09:42
Portsmouth
56°F
SW 5 mph
Feels like: 56°F
Precip: 4%
World Resorts USA Portsmouth Weather

7 Day Weather Forecast

09.15
tue
DAY
60°F
W 6 mph
precip
3%
NIGHT
56°F
NE 8 mph
precip
11%
09.16
wed
DAY
74°F
NE 9 mph
precip
13%
NIGHT
66°F
S 2 mph
precip
12%
09.17
thu
DAY
66°F
SW 5 mph
precip
24%
NIGHT
62°F
SE 6 mph
precip
52%
09.18
fri
DAY
72°F
W 5 mph
precip
3%
NIGHT
56°F
S 8 mph
precip
4%
09.19
sat
DAY
60°F
W 7 mph
precip
13%
NIGHT
62°F
N 16 mph
precip
82%
09.20
sun
DAY
66°F
E 6 mph
precip
42%
NIGHT
60°F
NE 6 mph
precip
14%
09.21
mon
DAY
60°F
W 12 mph
precip
16%
NIGHT
58°F
SW 9 mph
precip
18%

Portsmouth Sea Water Temperature in September, °F

Select Year: 2026 2025 2024

The average sea surface temperature in September 2026 for Portsmouth was 18.8°F. The maximum and minimum values were 17.1°F and 19.6°F respectively.

Portsmouth on the Weather Map

Best Time to Visit Portsmouth
The most sunny months:
November 16 days
October 14 days
July 13 days
The most warm months:
July 82.8 °F
August 80.9 °F
June 76.1 °F
Warmest sea temperature:
August 67.0 °F
July 65.2 °F
September 63.6 °F
The most cold months:
January 30.9 °F
February 32.1 °F
December 36.4 °F
The most rainy months:
July 3 days
August 2 days
October 2 days
The most windy months:
January 9 mph
March 9 mph
November 9 mph
more details