It could busy any day. That includes Monday. Just go when its best for you, gain an hour early access by staying at a park hotel.
I recommend a week day because ppl are usually at work tho from my experience if you are going on a weekend then travel early in the morning like 8 am or 9
Ots best to go when there's no time off from school i.e. spring break. The least busy day I saw was a Sunday but it was in March not during school break
I went on a Friday which was a school day and it was very sparse i went again on a sat and it was more crowded but not a crazy amount, so i assume as long as it is a Monday that school is in you should have way less crowd
Tuesdays are best
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