Weather in Brussels in September 2025
Average weather
Average temperature in Brussels in September
Going from a maximum of +32°C during the day to a minimum of +7°C during the night, the temperature in September averages around +24°C.
The average maximum temperature goes down 12% by the end of the month, compared with the beginning of the month, from +22°C to +19°C.
Is Brussels warm or cold in September?
Brussels is typically mild in September.
Maximum temperatures go down compared to the previous month from +23°C to +20°C. The minimum temperature also goes down from +14°C to +11°C.
Pack a light jacket as it will be warm in the day and cool in the evenings.
Take a look at how September is compared to other months in Brussels:
Climate in Brussels in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +23°C | +20°C | +15°C | ||||
| Min. temperature | ||||||
| +6°C | +3°C | -4°C | ||||
| Max. temperature | ||||||
| +36°C | +35°C | +26°C | ||||
| Rainfall | ||||||
| 67 mm | 65 mm | 65 mm | ||||
| Wind | ||||||
| 2 m/s | 3 m/s | 3 m/s | ||||
| Humidity | ||||||
| 73% | 78% | 82% | ||||
| Air pressure | ||||||
| 1015 HPa | 1016 HPa | 1014 HPa | ||||
| Sunny days | ||||||
| 5 | 5 | 4 | ||||
| Cloudy days | ||||||
| 7 | 8 | 10 | ||||
| Rainy days | ||||||
| 16 | 15 | 16 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September typically has worse weather conditions compared to August. It’s getting colder in September. From +23°C in the day, the average maximum temperature lowers to +20°C. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 67 mm to 65 mm. Humidity rises from 73% to 78%. Winds are stronger in comparison to August, going up from 2 m/s to 3 m/s on average. The amount of sunny days stay about the same, averaging 5 sunny days during the month.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 2 m/s getting up to 6 m/s which is a medium breeze. You can feel it, especially getting out of the water.
The average wind speed in Brussels is gradually increasing during September, going from 2 m/s to 2 m/s over the course of the month.
Rain
How was the weather last September in Brussels?
Climate Change over Years
The climate in Brussels in September has not changed much over the last 43 years.
The average temperature was the lowest in 1985 (+13°C) and the highest in 2022 (+17°C). The driest year was 1996 with only 558 mm of rainfall, and the wettest year was 2022 with 1284 mm.
FAQ
Is September a good time to visit Brussels?
Can you sunbathe in Brussels in September?
Is Brussels rainy in September?
Is it sunny in Brussels in September?
Other cities in Belgium
Monthly weather in Brussels
Source of the data
For this page, we’ve looked at the typical weather in Brussels, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.