Portsmouth Harbor Water Temperature

(Today) 2024

17.8°C / 64.1°F

The water will feel medium. The water will feel a bit chilly in just bathers / swimming costume. If you plan on wearing a wetsuit 4/3mm should be thick enough.

*Live data from Seavey Island, ME: 17.2°C / 63°F

Current weather

15°C / 60°F
(light rain)
Partly cloudy
Wind
10 mph
Humidity
82%

The measurements for the water temperature in Portsmouth Harbor, Maine are provided by the daily satellite readings provided by the NOAA. The temperatures given are the sea surface temperature (SST) which is most relevant to recreational users.

*Live data may vary from satellite readings for a number of reasons. These include local factors, depth of smapling and time of day.

Water temp by month

Monthly average max / min water temperatures

The graph below shows the range of monthly Portsmouth Harbor water temperature derived from many years of historical sea surface temperature data.

Portsmouth Harbor average maximum / minimum water temperatures
Maximum and minimum monthly sea temperatures in Portsmouth Harbor
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Min °C 3.8 2.4 2.1 3.7 5.2 10.2 14.9 16.9 14.3 9.8 8.3 5.7
Max °C 6.7 5.2 5.1 7.8 11.8 16.4 19.7 20.4 18.9 16.7 11.5 9.6
Min °F 40 37.4 37 40.3 44 52.8 60.7 63.8 59.6 52.4 48.2 43.8
Max °F 42.9 40.2 40 44.4 50.6 59 65.5 67.3 64.2 59.3 51.4 47.7

The warmest water temperature is in August with an average around 65.5°F / 18.6°C. The coldest month is March with an average water temperature of 38.5°F / 3.6°C.

7 day tide forecast for Portsmouth Harbor

SunMonTueWedThuFriSat
  • High 2:44am
    (2.51m)
  • Low 8:51am
    (0.38m)
  • High 2:55pm
    (2.65m)
  • Low 9:22pm
    (0.31m)
  • High 3:26am
    (2.4m)
  • Low 9:31am
    (0.47m)
  • High 3:36pm
    (2.62m)
  • Low 10:08pm
    (0.36m)
  • High 4:13am
    (2.3m)
  • Low 10:16am
    (0.54m)
  • High 4:23pm
    (2.58m)
  • Low 11:00pm
    (0.4m)
  • High 5:06am
    (2.23m)
  • Low 11:07am
    (0.59m)
  • High 5:17pm
    (2.58m)
  • Low 11:57pm
    (0.41m)
  • High 6:04am
    (2.2m)
  • Low 12:03pm
    (0.59m)
  • High 6:16pm
    (2.62m)
  • Low 12:58am
    (0.37m)
  • High 7:07am
    (2.23m)
  • Low 1:05pm
    (0.54m)
  • High 7:20pm
    (2.7m)
  • Low 2:02am
    (0.27m)
  • High 8:11am
    (2.35m)
  • Low 2:09pm
    (0.41m)
  • High 8:23pm
    (2.84m)
7 day tide times for Portsmouth Harbor

*These tide times are estimates based on the nearest accurate location (Fort Point, Portsmouth Harbor, New Hampshire) and may differ by up to half an hour depending on distance. Please note, the tide times given are not suitable for navigational purposes.