Halloween time at Disneyland

[xMagicMinniex]

Hi! This October, my family and I are gong to Disneyland for 3-4 days. We want to take advantage of being there during this time and go to the Halloween Time party they hold at night. I've tried to figure out exactly which days they're held on, but I can't find anything on the internet and the Official Guide that I bought only says 'select nights'.

Can anyone tell me which nights they parties are usually held on? Any help is really appreciated.