Weather data I have gleaned for Brussels at the start of September
Average high 20C/68F
Average low 10C/50F
Average rainfall in September 3.5 inches
On paper that's very similar to where I live (Boston). About 5F cooler in Brussels and slightly wetter.
The averages only paint part of the picture, though, as we all know.
So I ask - what's it really like? Is the weather very changeable during a single day? When it rains is it soft rain or RAIN!! rain? Windy? If you've been to Brussels (or Bruges, Ghent or Antwerp in mid-September, what did you experience?
We will be headed to Islay after Belgium, which is very likely to be cooler and very changeable hour-by-hour. I'm making packing lists now and hoping that the layers + waterproof gear we need for Islay will serve us in Belgian urban areas.