Portstewart weather in September 2025

Q: How warm is it in Portstewart in September?

Daytime temperatures usually reach 15°C in Portstewart in September, falling to 9°C at night.

Q: How sunny is it in Portstewart in September?

There are normally 3 hours of bright sunshine each day in Portstewart in September - that's 26% of daylight hours.

Q: How warm is the sea around Portstewart in September?

The average sea temperature around Portstewart in September is 14°C.

Q: Does it rain in Portstewart in September?

There are usually 20 days with some rain in Portstewart in September and the average monthly rainfall is 107mm.

Expect daytime maximum temperatures of 15°C in Portstewart, Northern Ireland in September based on long-term weather averages. There are 3 hours of sunshine per day on average with 20 days with some rainfall and typically 107 mm of rainfall in the month.

15
15°C max day temperature
3
3 hours of sunshine per day
20
20 days with some rainfall
9
9°C min night temperature
13
13 hours of daylight per day
0
No heat & humidity
107
107 mm of monthly rainfall
3
3 (Moderate) UV index
14
14°C sea temperature

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The September weather guide for Northern Ireland (Portstewart) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm) | Imperial (°F / inches)

More about the UK

How warm is it in Portstewart in September?

Daytime temperatures usually reach 15°C in Portstewart in September, falling to 9°C at night.

How sunny is it in Portstewart in September?

There are normally 3 hours of bright sunshine each day in Portstewart in September - that's 26% of daylight hours.

How warm is the sea around Portstewart in September?

The average sea temperature around Portstewart in September is 14°C.

Does it rain in Portstewart in September?

There are usually 20 days with some rain in Portstewart in September and the average monthly rainfall is 107mm.

Portstewart September sunrise & sunset times

Browse the sunrise and sunset times for Portstewart in September 2025. Select a month to view Portstewart sunrise and sunset times for the next 12 months.

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