Portstewart Sea Temperature

(Today) 2025

9.8°C / 49.6°F

The water will feel cold. All but the most ardent watersports enthusiasts will be thinking of packing up for the winter. If not we'd suggest a thick 5/4mm wetsuit along with some boots and a hood.

Current weather

11°C / 51°F
(scattered clouds)
Partly cloudy
Wind
11 mph
Humidity
75%

The measurements for the water temperature in Portstewart, N Ireland 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 Portstewart water temperature derived from many years of historical sea surface temperature data.

Portstewart average maximum / minimum water temperatures
Maximum and minimum monthly sea temperatures in Portstewart
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Min °C 7.9 7.6 7.3 7.8 9.2 9.5 11.9 13 13.1 12.2 11.1 9.4
Max °C 10.1 9.1 9.2 9.9 11.1 13.8 14.8 15.5 14.9 14.2 13.3 11.7
Min °F 47.1 46.2 45.9 46.8 49.3 50.8 54.5 56.4 56.3 54.8 52.9 49.8
Max °F 49.3 47.7 47.8 48.9 51.2 55.1 57.4 58.9 58.1 56.8 55.1 52.1

The warmest water temperature is in August with an average around 57.6°F / 14.2°C. The coldest month is March with an average water temperature of 46.8°F / 8.2°C.

7 day tide forecast for Portstewart

ThuFriSatSunMonTueWed
  • Low 3:37am
    (0.42m)
  • High 10:00am
    (1.88m)
  • Low 3:41pm
    (0.56m)
  • High 10:10pm
    (1.91m)
  • Low 4:50am
    (0.62m)
  • High 11:05am
    (1.65m)
  • Low 4:29pm
    (0.74m)
  • High 11:24pm
    (1.78m)
  • Low 7:02am
    (0.74m)
  • High 12:34pm
    (1.48m)
  • Low 5:25pm
    (0.89m)
  • High 1:52am
    (1.75m)
  • Low 8:33am
    (0.75m)
  • High 2:11pm
    (1.4m)
  • Low 6:42pm
    (0.99m)
  • High 3:10am
    (1.79m)
  • Low 9:43am
    (0.74m)
  • High 3:24pm
    (1.38m)
  • Low 8:29pm
    (1m)
  • High 4:09am
    (1.82m)
  • Low 10:42am
    (0.73m)
  • High 4:22pm
    (1.4m)
  • Low 9:39pm
    (0.94m)
  • High 4:58am
    (1.82m)
  • Low 11:29am
    (0.72m)
  • High 5:05pm
    (1.46m)
  • Low 10:25pm
    (0.86m)
7 day tide times for Portstewart

*These tide times are estimates based on the nearest accurate location (Portrush, Northern Ireland) and may differ by up to half an hour depending on distance. Please note, the tide times given are not suitable for navigational purposes.