Couple of things to consider:  -Merlin recently made Halloween an included day for most passes. -The excluded days, somewhat ironically, tend to be a bit quieter because: There's less passholders People expect those days to be busy so avoid them -The weather was forecast to be a bit rubbish, which can put passholders off -There were 2 severe cases of bad weather, including electrical storms in the nearby area, shutting down most rides. That, along with the rubbish weather, meant people left earlier.   The park today didn't feel as busy as it was yesterday. Nor did it feel as busy as it was last Halloween. However, the park was still extremely busy and lively.