Belfast
September
Weather in Belfast for September 2025
Your guide to Belfast weather in September - trends and predictions
In general, the average temperature in Belfast at the beginning of September is 18.6 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 13.3 °C by the end of September.
Belfast in September brings notable rainfall, with an average of 18 rainy days and a total precipitation of 101.9 mm.
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Temperatures
Rain 🌧️
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12
Dry days
18
Rainy days
0
Snow days
16°/9°
Temperatures
23 km/h
Avg max wind
84 %
Avg humidity
Belfast in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  16° | 2 18° | 3  18° | 4 17° | 5  19° | 6 21° | 7 21° |
| 8 21° | 9 19° | 10  17° | 11 14° | 12 14° | 13  14° | 14 16° |
| 15  13° | 16  16° | 17  17° | 18 15° | 19 17° | 20 17° | 21 15° |
| 22 15° | 23 14° | 24 15° | 25 13° | 26 12° | 27 13° | 28 14° |
| 29 14° | 30 12° |
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Temperatures trend during September in Belfast
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. | Patchy rain possible | 16° /11° | 0.7 mm | 4 | |
| 2 Sept. | Patchy rain possible | 18° /10° | 4.7 mm | 4 | |
| 3 Sept. | Sunny | 18° /9° | 0.3 mm | 5 | |
| 4 Sept. | Sunny | 17° /9° | 0.9 mm | 5 | |
| 5 Sept. | Partly cloudy | 19° /10° | 0 mm | 5 | |
| 6 Sept. | Partly cloudy | 21° /12° | 0 mm | 6 | |
| 7 Sept. | Patchy rain possible | 21° /12° | 1.2 mm | 5 | |
| 8 Sept. | Partly cloudy | 21° /11° | 0.9 mm | 5 | |
| 9 Sept. | Patchy rain possible | 19° /11° | 0.7 mm | 5 | |
| 10 Sept. | Moderate or heavy rain shower | 17° /10° | 8.1 mm | 4 | |
| 11 Sept. | Light rain shower | 14° /8° | 4.1 mm | 4 | |
| 12 Sept. | Partly cloudy | 14° /5° | 0.6 mm | 4 | |
| 13 Sept. | Overcast | 14° /5° | 0.6 mm | 4 | |
| 14 Sept. | Overcast | 16° /9° | 0.2 mm | 4 | |
| 15 Sept. | Moderate rain | 13° /8° | 9.2 mm | 4 | |
| 16 Sept. | Cloudy | 16° /7° | 0 mm | 4 | |
| 17 Sept. | Light rain | 17° /10° | 8.4 mm | 4 | |
| 18 Sept. | Patchy rain possible | 15° /9° | 2.2 mm | 4 | |
| 19 Sept. | Light rain | 17° /9° | 4.1 mm | 4 | |
| 20 Sept. | Light rain shower | 17° /9° | 2.3 mm | 4 | |
| 21 Sept. | Light rain shower | 15° /7° | 0.7 mm | 4 | |
| 22 Sept. | Light rain shower | 15° /8° | 1.6 mm | 4 | |
| 23 Sept. | Light drizzle | 14° /6° | 0.6 mm | 4 | |
| 24 Sept. | Light rain shower | 15° /10° | 7.4 mm | 4 | |
| 25 Sept. | Patchy rain possible | 13° /9° | 1.9 mm | 4 | |
| 26 Sept. | Light rain shower | 12° /7° | 14.5 mm | 3 | |
| 27 Sept. | Light rain shower | 13° /6° | 10.6 mm | 3 | |
| 28 Sept. | Light rain shower | 14° /6° | 2.1 mm | 4 | |
| 29 Sept. | Patchy rain possible | 14° /7° | 1 mm | 4 | |
| 30 Sept. | Light rain shower | 12° /8° | 12.2 mm | 3 | |
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Important Notice
Our weather forecast for Belfast in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Belfast forecast closer to your planned date for the most up-to-date weather information.
Belfast in September - FAQ
What are the expected maximum and minimum temperatures in Belfast during September?
Enjoy moderate daytime temperatures of up to 16° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Belfast during September?
Significant rainfall exceeding 101.9 mm is expected in Belfast during September, occurring over more than 18 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Belfast during September?
The average wind speed in Belfast during September is 23 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Belfast
Explore the daily rainfall trends and prepare for Belfasts September weather 💧
UV exposure in Belfast during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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