September in Belfast, Northern Ireland, typically marks a transition from summer to autumn. Expect a mix of sunny days and overcast periods, with temperatures gradually cooling. Average highs generally range from 14-17C (57-63F), while overnight lows dip to around 8-11C (46-52F). Rainfall is common throughout the month, though it’s usually lighter and less frequent than in the later autumn and winter months. Daylight hours noticeably decrease as September progresses.
Understanding the typical climatic conditions of Belfast in September is essential for travelers planning visits. Packing appropriately for varied weather, including light layers, a waterproof jacket, and comfortable shoes, is crucial for a pleasant experience. This information is also valuable for local businesses and event organizers, allowing them to prepare accordingly and make informed decisions about outdoor activities and scheduling. Historically, September has been a harvest month in the region, and the moderating influence of the Atlantic Ocean plays a significant role in shaping the climate.