I should know this...

[12_Ears_Dad]

My 30 days out starts tomorrow.. when's the earliest I should check? Midnight or at that parks closure for this evening?

 

[englanddg]

My 30 days out starts tomorrow.. when's the earliest I should check? Midnight or at that parks closure for this evening?

Midnight Eastern, pretty sure.

 

[sxeensweet]

My 30 days out starts tomorrow.. when's the earliest I should check? Midnight or at that parks closure for this evening?

Usually it's midnight eastern but if the last park is open until 1am eastern and so on they will not be available to book until the last park closes.
Looks like MK closes at 11pm eastern tonight (last park closing tonight) so you should be good at midnight eastern tonight.