September in Belfast averages 30°C (86°F) during the day and 26°C (79°F) at night. Quite a bit of rainfall is typical this month, with around 164 mm (6.5 in) on average. An umbrella is a good idea.
September in Belfast has its charm, but if you're looking for destinations with pleasant temperatures and sunny skies, our weather planner can help you explore other options in the world.
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Pick a month to see the average temperature, rainfall and sunshine in Belfast - and find the best time to visit.
49-year average (1976-2025)
Based on our historical records, temperatures in Belfast typically stay consistent throughout September, with daily highs averaging around 30°C (86°F). Nights are warm, with lows around 26°C (79°F).
49-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Browse day-by-day weather records for Belfast spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Based on 21 years of weather observations in Belfast between 2005 and 2026, these are the recorded extremes.
Find out more about the weather in Jamaica and which places have the best travel conditions in this month. See all of Jamaica in September →
Perfect weather is subjective. On this map perfect weather has been defined with temperatures between 20°C (68°F) and 29°C (84°F) and not too much precipitation (less than 90 mm (3.5 in) a month).
Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). Also bring a poncho, it will rain a lot! Waterproof everything you can. You'll definitely want to pack sunglasses and sunscreen. There will be plenty of bright sunshine this month.
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Temperature Rainfall Sunshine Humidity
See the full Belfast climate overview or explore weather in Jamaica.
Where to go in September - average daytime high across popular destinations.
Runaway Bay
31°C (88°F) Falmouth31°C (88°F) Montego Bay32°C (90°F) Ocho Rios
31°C (88°F) Kingston30°C (86°F) Treasure Beach
31°C (88°F) Negril31°C (88°F) Port Antonio30°C (86°F) Need travel inspiration? Check out our bucket list articles and be inspired.
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