No. It's in a hall. The location is called Sjiwa (named after the Hindu God which is called Shiva in English).
In principle, rain and cold weather would be no big problem. Except for the fact that you have to get to the club and back to Kasteel de Berckt (or whereever you are staying).
Hmm, the site I was checking still gives a 40% chance of rain all weekend I'll pack an umbrella just to be safe.
The only problem with these kinds of events is that during the day it's shirt weather, the evening is sweater weather, the night is jacket weather and inside the venue it's almost too hot for clothing at all!