In September, Ireland transitions from summer to autumn, experiencing mild temperatures, moderate rainfall, gentle winds, and decreasing daylight hours.
Met Éireann’s 1991-2020 averages put typical September highs at 16 to 17.5°C (60 to 64°F) and lows at 9.5 to 11.5°C (49 to 53°F). Rainfall ranges from about 60 mm (2.4 inches) around Dublin to 130 mm (5.1 inches) on the Kerry coast, and you lose about two hours of daylight between the start and end of the month.
Overview of the Weather in Ireland in September
- Temperature: Average daily temperatures range from lows of 10°C (50°F) to highs of 17°C (63°F).
- Rainfall: Varies by region; for example, Dublin Airport averages 63 mm (2.5 inches), while Valentia in Co Kerry sees about 130 mm (5.1 inches).
- Rain Days: Expect 10 to 17 days with at least 1 mm of rain, with fewer in the east and more in the west.
- Wind Speed: September experiences moderate winds, with average speeds of around 15 to 22 km/h (10 to 14 mph) at Met Éireann’s main weather stations.
- Sunshine: Around 4 hours of bright sunshine a day on average, from 3.8 hours at Malin Head to 4.4 hours at Dublin Airport.
- Daylight Hours: Approximately 11.5 to 13.5 hours per day; sunrise around 6:35 AM, sunset near 8:15 PM in Dublin at the beginning of the month, with decreasing daylight as the month progresses.
September Weather in Ireland: A Closer Look
Temperature
September in Ireland is generally mild, with average temperatures ranging from 10°C (50°F) to 17°C (63°F). Coastal areas, influenced by the Atlantic Ocean, tend to be milder, while inland regions may experience slightly cooler conditions.
The station averages back this up. Valentia in Co Kerry has the mildest September nights, at 11.7°C (53°F), while Dublin Airport drops to 9.5°C (49°F). Shannon Airport has the warmest afternoons, averaging 17.5°C (64°F).
Here is how September compares at Met Éireann’s main weather stations, with Armagh included for Northern Ireland:
Rainfall
Rainfall varies across Ireland in September. Eastern regions like Dublin receive about 63 mm (2.5 inches), making them relatively drier. In contrast, western areas such as Valentia in Co Kerry experience higher rainfall, averaging 130 mm (5.1 inches) during the month.
Belmullet in Co Mayo (103 mm) and Malin Head in Co Donegal (95 mm) are also on the wet side. If you are heading that way, our travel guide for the west coast will help you plan the route.
Wind Speed
September experiences moderate winds, with average speeds of around 15 to 22 km/h (10 to 14 mph) at most weather stations. Coastal regions, especially along the west, may experience stronger gusts due to Atlantic weather systems.
Gales are not common, but they do happen. Malin Head averages about two gale days in September, and in September 2025 Mace Head in Co Galway recorded a gust of 109 km/h (68 mph). Golfers can see how the month compares in our golf weather guide for Ireland.
Daylight Hours
Daylight decreases in September, with approximately 11.5 to 13.5 hours of light daily. The sun typically rises around 6:35 AM and sets near 8:15 PM in Dublin at the beginning of the month, with daylight hours shortening as autumn approaches.
By 30 September, sunrise in Dublin is around 7:25 AM and sunset just after 7:00 PM, so you lose roughly two hours of daylight over the month. Galway and the west see sunrise and sunset about 11 minutes later than Dublin.
The darker evenings later in the month also give you a better chance of spotting the Northern Lights in Ireland when solar activity is high.
Sunshine
Expect around 4 hours of sunshine a day. Dublin Airport averages 4.4 hours a day in September, while Malin Head in Co Donegal averages 3.8 hours.
How Did Recent Septembers Compare?
Averages only tell part of the story, and the last two Septembers show how much the month can swing.
- September 2026: Provisionally the second warmest September on record, with a national mean temperature of 15.22°C, 1.62°C above the 1991-2020 average. Rainfall was 117% of average, and Phoenix Park in Dublin reached 25.2°C (77°F) on 14 September.
- September 2025: Cooler and wetter than normal. Temperatures were 0.1°C to 0.8°C below average at the stations in Met Éireann’s monthly bulletin, and rainfall ran at 106% to 191% of normal.
So pack for both: a warm September afternoon can feel like summer, but a cool, wet week is always possible.
Ireland vs Northern Ireland Weather in September
While both regions share similar climates, subtle differences exist:
- Temperature: Northern Ireland’s average temperatures are very similar. At Armagh, September days average 9.7°C (49°F) to 17.3°C (63°F), compared with 9.5°C (49°F) to 16.9°C (62°F) at Dublin Airport.
- Rainfall: Armagh averages 65 mm (2.6 inches) in September, close to Dublin Airport’s 63 mm (2.5 inches) and well below the west coast of the Republic.
- Wind: Both regions experience moderate winds in September, with coastal areas experiencing higher gusts.
- Daylight: Daylight hours are similar, with both regions experiencing about 11.5 to 13.5 hours of daylight during September.
In summary, while Ireland and Northern Ireland share comparable September weather patterns, the bigger difference is east versus west: the Atlantic coast is milder at night and much wetter than the east coast.
Is September a Good Time to Visit Ireland?
For many visitors, yes. Early September still has more than 13 hours of daylight, average highs sit around 17°C (63°F), and the summer rush eases once Irish schools go back (see the school holiday dates).
The trade-off is more rain and shorter days by the end of the month, so plan outdoor highlights for the first half of September where you can and keep a few indoor options up your sleeve. Our Ireland trip planner is a good place to start.
What to Pack for Ireland in September
- A waterproof jacket with a hood, as rain falls on 10 to 17 days of the month on average.
- Layers: a T-shirt for mild afternoons and a fleece or jumper for evenings around 10°C (50°F).
- Waterproof walking shoes or boots.
- A compact umbrella for city days.
Travelling light? Our Ireland city break packing list shows how to fit it all into one small bag.
September Weather in Ireland: FAQs
Is September a rainy month in Ireland?
September is moderately wet. Met Éireann’s 1991-2020 averages range from about 62 mm of rain at Casement Aerodrome in Dublin to 130 mm at Valentia in Kerry, with at least 1 mm of rain on 10 to 17 days.
How warm is Ireland in September?
Typical daytime highs are 16 to 17.5°C (60 to 64°F) and nights are 9.5 to 11.5°C (49 to 53°F). Warm spells do happen: Phoenix Park in Dublin hit 25.2°C (77°F) on 14 September 2026.
Is September warmer than October in Ireland?
Yes. Dublin Airport averages a high of 16.9°C (62°F) in September and 13.6°C (56°F) in October, and October is wetter there too, at 78 mm against 63 mm.
How many hours of daylight does Ireland get in September?
Dublin has about 13 hours 40 minutes of daylight on 1 September and about 11 hours 40 minutes by 30 September. Day and night are roughly equal around the autumn equinox on 23 September.
Does it snow in Ireland in September?
Snow in September is extremely rare. Dublin Airport averages zero days of snow or sleet in September over 1991-2020.
Figures checked against Met Éireann’s 30-year averages and Met Office Armagh station data in October 2026.
