Weather in Ireland in September

In September, Ireland transitions from summer to autumn, experiencing mild temperatures, moderate rainfall, gentle winds, and decreasing daylight hours.

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, Kilkenny averages 69 mm (2.7 inches), while Kincasslagh sees about 144 mm (5.7 inches).
• Wind Speed: September experiences moderate winds, with average speeds around 25 km/h (15.5 mph).
• Daylight Hours: Approximately 11 to 13 hours per day; sunrise around 6:41 AM, sunset near 8:14 PM 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.

Rainfall

Rainfall varies across Ireland in September. Eastern regions like Kilkenny receive about 69 mm (2.7 inches), making them relatively drier. In contrast, western areas such as Kincasslagh experience higher rainfall, averaging 144 mm (5.7 inches) during the month.

Wind Speed

September experiences moderate winds, with average speeds around 25 km/h (15.5 mph). Coastal regions, especially along the west, may experience stronger gusts due to Atlantic weather systems.

Daylight Hours

Daylight decreases in September, with approximately 11 to 13 hours of light daily. The sun typically rises around 6:41 AM and sets near 8:14 PM at the beginning of the month, with daylight hours shortening as autumn approaches.

Ireland vs Northern Ireland Weather in September 2025

While both regions share similar climates, subtle differences exist:

• Temperature: Northern Ireland’s average temperatures are slightly lower, with daily averages around 13°C (55°F), compared to Ireland’s average of 14°C (57°F).
• Rainfall: Northern Ireland experiences marginally higher rainfall, averaging 80 mm (3.1 inches) in September, compared to Kilkenny’s 69 mm (2.7 inches).
• 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 to 13 hours of daylight during September.

In summary, while Ireland and Northern Ireland share comparable September weather patterns, Northern Ireland tends to be slightly cooler and wetter.