Londonderry weather in September 2026

Q: How warm is it in Londonderry in September?

Daytime temperatures usually reach 16°C in Londonderry in September, falling to 9°C at night.

Q: How sunny is it in Londonderry in September?

There are normally 4 hours of bright sunshine each day in Londonderry in September - that's 30% of daylight hours.

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

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

Q: Does it rain in Londonderry in September?

There are usually 17 days with some rain in Londonderry in September and the average monthly rainfall is 94mm.

Expect daytime maximum temperatures of 59°F in Londonderry, Northern Ireland in September based on long-term weather averages. There are 3 hours of sunshine per day on average with 21 days with some rainfall and typically 4.3 inches of rainfall in the month.

59
59°F max day temperature
3
3 hours of sunshine per day
21
21 days with some rainfall
46
46°F min night temperature
13
13 hours of daylight per day
0
No heat & humidity
4.3
4.3 inches of monthly rainfall
3
3 (Moderate) UV index

More about Londonderry

Londonderry by month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Recommended for Northern Ireland

Rural Retreats: Holiday properties with spa facilities

Sale

Book properties with jacuzzis, heated pools & saunas
Browse stays in Suffolk with many other great facilities
Filter search by selecting holiday preferences

Go to Rural Retreats deal >>

View all Rural Retreats offers

The September weather guide for Northern Ireland (Londonderry) 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) | Imperial (°F)

More about the UK

How warm is it in Londonderry in September?

Daytime temperatures usually reach 61°F in Londonderry in September, falling to 48°F at night.

How sunny is it in Londonderry in September?

There are normally 4 hours of bright sunshine each day in Londonderry in September - that's 30% of daylight hours.

How warm is the sea around Londonderry in September?

The average sea temperature around Londonderry in September is 57°F.

Does it rain in Londonderry in September?

There are usually 17 days with some rain in Londonderry in September and the average monthly rainfall is 3.7 inches.

Londonderry September sunrise & sunset times

Browse the sunrise and sunset times for Londonderry in September 2026. Select a month to view Londonderry sunrise and sunset times for the next 12 months.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec