Weather in Brussels for September 2025
Until now, September 2025 in Brussels is slightly cooler than the historical average by -1.4 °C.
The forecast for the next days in Brussels predicts a temperature of 18.8 °C, which is cooler than the historical average.
In general, the average temperature in Brussels at the beginning of September is 25.4 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 15.6 °C by the end of September.
Brussels experiences heavy rainfall in September, with over 20 rainy days and an average total precipitation 79 mm.
Temperatures
Rain 🌧️
Brussels Weather September
Temperatures trend during September in Brussels
September weather in Brussels day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Sunny | 25° /14° | 8 mm | 6 | |
| 2 Sept. | Sunny | 25° /14° | 1.3 mm | 6 | |
| 3 Sept. |  Patchy rain possible | 25° /14° | 0.8 mm | 6 | |
| 4 Sept. | Sunny | 25° /13° | 0.6 mm | 6 | |
| 5 Sept. | Sunny | 25° /14° | 4.1 mm | 6 | |
| 6 Sept. | Sunny | 25° /14° | 3.6 mm | 6 | |
| 7 Sept. | Sunny | 28° /14° | 1 mm | 7 | |
| 8 Sept. | Sunny | 25° /15° | 3 mm | 6 | |
| 9 Sept. | Patchy rain possible | 21° /14° | 3.2 mm | 5 | |
| 10 Sept. |  Heavy rain at times | 22° /14° | 1.8 mm | 5 | |
| 11 Sept. | Patchy rain possible | 21° /13° | 2.5 mm | 5 | |
| 12 Sept. | Light rain shower | 21° /11° | 0.6 mm | 5 | |
| 13 Sept. | Sunny | 19° /11° | 5.2 mm | 5 | |
| 14 Sept. | Patchy rain possible | 20° /12° | 3.9 mm | 5 | |
| 15 Sept. | Patchy rain possible | 21° /12° | 1 mm | 5 | |
| 16 Sept. | Patchy rain possible | 19° /12° | 0.8 mm | 0.7 | |
| 17 Sept. | Patchy rain possible | 19° /11° | 0.2 mm | 0.3 | |
| 18 Sept. | Sunny | 26° /14° | 0 mm | 1.1 | |
| 19 Sept. | Sunny | 31° /15° | 0 mm | 1 | |
| 20 Sept. |  Moderate rain | 22° /14° | 5 mm | 0.4 | |
| 21 Sept. | Patchy rain possible | 20° /11° | 0.9 mm | 3 | |
| 22 Sept. | Patchy rain possible | 18° /9° | 0.9 mm | 3 | |
| 23 Sept. | Patchy rain possible | 15° /9° | 0.3 mm | 3 | |
| 24 Sept. | Patchy rain possible | 17° /8° | 0.6 mm | 3 | |
| 25 Sept. | Patchy rain possible | 15° /8° | 0.8 mm | 3 | |
| 26 Sept. | Patchy rain possible | 16° /10° | 0.6 mm | 3 | |
| 27 Sept. | Sunny | 16° /7° | 0 mm | 4 | |
| 28 Sept. |  Partly cloudy | 17° /7° | 0 mm | 4 | |
| 29 Sept. | Patchy rain possible | 12° /10° | 0.1 mm | 3 | |
| 30 Sept. |  Overcast | 16° /7° | 1.5 mm | 4 | |
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Guide for Brussels in September
In September, Brussels, Belgium experiences a transition from the lingering warmth of summer to the cooler temperatures of autumn. At the beginning of the month, the weather in Brussels is generally mild and pleasant, with average temperatures around 16°.
The city experiences a mix of sunny days and occasional rainfall, with an average of 14 rainy days throughout the month. As September progresses, the temperatures gradually begin to decrease, and by the end of the month, the average temperature in Brussels hovers around 13°.
The evenings become notably cooler, making it advisable for visitors to bring a light jacket or sweater when exploring the city after sunset.
The weather in Brussels during September is characterized by a comfortable and temperate climate, making it an ideal time to explore the city's charming streets, parks, and historic landmarks.
However, visitors should be prepared for the possibility of occasional showers, especially towards the end of the month. Overall, September offers a pleasant and inviting atmosphere for travelers to enjoy the cultural delights of Brussels.
Brussels in September - FAQ
September rainfall patterns in Brussels
UV exposure in Brussels during September
Quick links
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