Hey guys, I'm looking to head over to the states in October and I am currently trying to look at opening dates for Magic Mountain. However, but they blank out future dates. 

Aren't they open every day now?

It's a year round park I believe so you should be fine!

Also October is Fright Fest season so at a minimum you'd expect weekends to be sweet 

It's open every day. I did it in November .. the only downside is it gets pretty cold (was 5-7 degrees C for my visit) which also means the coasters run pretty slow

Of course! Good time of year as well - especially during the week. I was able to ride twisted colossus back to back for an hour!