Monthly climate guide
Brussels weather in September
With highs near 21°C (69°F) and lows around 11°C (51°F), September feels mild in Brussels. Rainfall averages about 52 mm (some rain) and the sky is often cloudy. Daytime highs are 3°C cooler than August and 5°C warmer than October.
What stands out in September
- In Brussels, September is early autumn.
- It cools down fast from here: October is about 5°C cooler.
- Comfortable temperatures make it easy to walk between Manneken Pis and Grand-Place.
- Skies are at their clearest this time of year.
Avg high
21°C
69°F
Avg low
11°C
51°F
Rainfall
52 mm
some rain
Humidity
78%
relative
Sky
61%
cloud · often cloudy
Brussels weather by month
Show the monthly averages as a table
| Month | Avg high | Avg low | Rain | Humidity | Cloud cover |
|---|---|---|---|---|---|
| January | 6°C / 43°F | 1°C / 33°F | 71 mm | 93% | 80% |
| February | 7°C / 45°F | 0°C / 32°F | 54 mm | 89% | 71% |
| March | 11°C / 52°F | 2°C / 35°F | 49 mm | 84% | 66% |
| April | 15°C / 60°F | 5°C / 40°F | 34 mm | 77% | 63% |
| May | 19°C / 65°F | 8°C / 46°F | 54 mm | 76% | 67% |
| June | 22°C / 71°F | 11°C / 52°F | 69 mm | 75% | 70% |
| July | 24°C / 74°F | 13°C / 56°F | 72 mm | 74% | 67% |
| August | 24°C / 74°F | 13°C / 56°F | 68 mm | 74% | 65% |
| September | 21°C / 69°F | 11°C / 51°F | 52 mm | 78% | 61% |
| October | 16°C / 60°F | 8°C / 46°F | 64 mm | 85% | 71% |
| November | 10°C / 51°F | 4°C / 39°F | 56 mm | 91% | 74% |
| December | 7°C / 45°F | 2°C / 36°F | 84 mm | 93% | 79% |
What to pack for September
- T-shirts plus a light layer for the evening
- Comfortable trainers or sandals for long walks
- A small travel umbrella, just in case
Is September a good time to visit Brussels?
Our Brussels guide recommends: May to September for the mildest weather; Brussels sees rain in every season, so pack a light jacket.
Try fries from a friterie and waffles from a proper bakery rather than the tourist stalls around the Grand-Place.
Best time to visit Brussels →Other Belgium cities in September
Cite or embed this data
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Brussels weather in September. WeatherCompare, 2026 (NASA POWER / ERA5, 2011–2020 monthly averages). https://weathercompare.eu/weather/belgium/brussels/september
<a href="https://weathercompare.eu/weather/belgium/brussels/september">Brussels weather in September</a> (WeatherCompare)
<iframe src="https://weathercompare.eu/embed/belgium/brussels" width="300" height="160" style="border:0;border-radius:12px" loading="lazy" title="Brussels weather in September"></iframe> <p style="font-size:12px"><a href="https://weathercompare.eu/weather/belgium/brussels/september">Brussels weather in September</a> – WeatherCompare</p>
Brussels in September: quick answers
Is September a good time to visit Brussels?
Yes. September is one of the best months for Brussels, with highs around 21°C and about 52 mm of rain.
How warm is Brussels in September?
Average highs are about 21°C (69°F) and average lows about 11°C (51°F), based on 10 years of daily data.
Does it rain a lot in Brussels in September?
Brussels typically gets around 52 mm of rain in September — some rain.
When is the best time to visit Brussels?
May to September for the mildest weather; Brussels sees rain in every season, so pack a light jacket.
Figures are long-term averages for the area around Brussels (NASA POWER / ERA5, 2011–2020), not a forecast for a specific year. For upcoming days, see the live multi-source forecast.