hi there

so, my favorite climbing halls are klimax in puurs, stone age in brussels (by ultimate one), also there is bouldering in Gent called Bleauklimzaal, and another in saint niklaas called city lizzard. I hope these options keep you busy, the two are lead climbing halls and other bouldering halls, i combined both, and was not such a huge fan of hungaria, but i hope you enjoy the above.
and yes, in winter impossible to be outside on rock, but...i usually go to fontein bleau, its a drive out to france but its a boulder paradise and has better weather, especially because friction caused by cold is good for bouldering. otherwise, also have Yoir, Frere, dynant or berdof in luxemburg, but weather is usually a barrier. But if you can make time then just hop off to france like in orpierre or le calangues. there are options!
As much as i am loving being back, im trying to get back to cold belgium so maybe our paths will cross
all the best