Halloween Party Days?

Does anyone know what days of the week the Halloween after hours event typically run on? I’m wanting to book a short 4 day trip for mid to late September. I would love to do the Halloween party and am hoping the 4 days I book now will fall on a Halloween party event. That way I secure the hotel booking now and can buy the Halloween party ticket once they go on sell for September if that makes sense. Thanks for any help on this!