It's planned for every day, weather permitting.
As many superlatives as you'll have seen people use when describing it and as great as it looks on video, nothing can prepare you for just how stunning it is live. I was lucky enough to be at the very front to see it this Saturday just gone and wow, the heat from the fire is amazing, and very welcome on colder evenings.
If you can watch it a few times I'd recommend watching it a bit further back as well. It's great up close, but further away it's easier to suspend reality and believe in the castle transformations that much more.