At PBH last July they had one on a Thursday, the year before we where at RPR over the 4th July period and they had a movie everynight we where there. will be there over the 4th this year at RPR, the only problem with the dive in movies is we cannot get to go anywhere as DD wants to stay in the pool for them, even though she could probably act them,she has seen them that many times
i know the dates at HRH for the dive in movies have changed based on the month so i no longer say saturdays for their movies.
they are flexible at times and do change the day of the week for them.
you can always get the schedule in advance to see if your ressie time will cover the day the dive in will be held.