Is the opening ceremony happen every night at Halloween Horror Nights?

Every Halloween Horror Nights at 6:30pm

Opening ceremony is only the first night... that's why it's an opening ceremony. Despite what Dave H says, not all reviews are paid for by Universal. I've been going for the past few years in a row and have a blast every time.

I went i just went harry potter rides and wait for hollween horner night

No

I don't think so. When I went in October, we just wait for the doors to open the went through the haunted houses.