Swimming in Portstewart in september 2025: Average sea temperature in september and tide times in september 2025
Average sea temperature in Portstewart in september 2025.
In september, according to seasonal norms, the sea temperature in Portstewart is:
Minimum: 56°F
Average: 58°F
Maximum: 59°F
Other useful seasonal weather averages in september:
- Outside temperature: 53°F to 60°F
- Most common weather: "Moderate rain at times"
- The wind blows at 6.2mph
- It rains a total of 4.1in, over 7 day(s).
Should we swim in Portstewart in september?
No... The water temperature in Portstewart in september is freezing
You won't be able to swim in Portstewart in september! The water temperature is freezing, reaching as low as 56°F (and only 59°F at best)! Our advice: if you are going to Portstewart this month, plan to sightsee and forget the beach!
Note also that in september, the climate is tolerable with an average outside temperature of 56°F, 4.1in of precipitation (over 7 days) and 89.59 % humidity.
Water and normal seasonal temperatures in Portstewart in september
| September | |||
| Average sea temperature | 58°F | ||
| Minimum sea temperature | 56°F | ||
| Maximum sea temperature | 59°F | ||
| Average outside temperature | 58°F | ||
| Maximum outside temperature | 61°F | ||
| Minimum outside temperature | 54°F | ||
| Wind speed | 16.2mph | ||
| Wind temperature | 50°F | ||
| Precipitation | 4.1in | ||
| Number of days of rain | 7 jour(s) (24%) | ||
| Humidity | 90% | ||
| Visibility in kilometers | 8.97km | ||
| Cloud cover | 58% | ||
| Our opinion | freezing swimming |
Chart of the tides in september 2025
Tide times in september 2025 in Portstewart
Swim elsewhere in Northern Ireland in september
| City | Average T° | Min. T° | Max. T° | Our opinion | Belfast in september | 58°F | 59°F | freezing swimming | Derry (Londonderry) in september | 58°F | 60°F | freezing swimming | Portrush in september | 58°F | 60°F | freezing swimming |
Swim in Northern Ireland in september: sea temperature by city