The temperatures in Belfast in September are usually low and can range between 10°C and 16°C.
You can expect about 3 to 8 days of rain in Belfast during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Belfast in September 2025.
If you’re planning to visit Belfast in the near future, we highly recommend that you review the 14 day weather forecast for Belfast before you arrive.
Temperatures
16° / 10°
Rainy Days
7
Snowy Days
0
Dry Days
23
Rainfall
99
mm
Sun Hours
7.7
Hrs
