Brussels · September
Run in the morning.
Cool month: average high 68°F, low 54°F. Humidity averages 77% — the limiting factor on most runs. Cool, runnable conditions throughout — morning still has the steadiest air and lightest wind.
Avg high / low
68° / 54°F
Humidity
77%
Rain days
15/mo
Wind
11 mph
What September feels like in Brussels
Sunrise
07:19
Mid-month average
Sunset
19:56
Mid-month average
Time-of-day breakdown
Morning
Coolest, driest air of the day. The window before sunrise is the most reliable comfortable hour.
Midday
Mild but UV and traffic peak. Workable if you don't mind shifting your pace.
Evening
Warm and runnable. Crowded routes but the air's typically calm.
What to wear running in Brussels in September
The kit for September in Brussels: shorts and a short-sleeve are the standard kit, a water-resistant cap or jacket on standby.
September vs the surrounding months
vs August
-5° avg high
-2 rain days
Brussels in August →
September
68°F avg high
15 rain days
Best: morning
vs October
+8° avg high
-2 rain days
Brussels in October →
Frequently Asked Questions
What is the best time of day to run in Brussels in September?+
Morning. Cool, runnable conditions throughout — morning still has the steadiest air and lightest wind.
What's the average temperature in Brussels in September?+
Average high 68°F, average low 54°F.
How does September compare to surrounding months in Brussels?+
Compared to August (avg high 73°F), September is cooler. Compared to October (avg high 60°F), September is warmer.
Does it rain often in Brussels in September?+
Expect about 15 measurable rain days in September, on average.