save your money and don't buy the ex pass.
when it rains, crowds tend to thin out.
you can do more at the studios as so many of the rides are indoors.
at simpsons, kang is outdoors. RRR outdoors also. that's 2 rides that could be affected.
the potter shows of the singing entertainment is done outdoors without cover overhead.
at ioa, you have 3 rides that are outdoors at seuss, P. flyers/small roller coaster near FJ are outdoors, Doom is outdoors
that's 6 at IOA that might or might not operate depending if it is a downpour type of rain.
the rides will operate outdoors in a light rain.
if it is a downpour or if lighening is within 5 miles, they will be shutdown.
go and do the parks but choose footwear that can handle the rain.
nothing worse than getting blisters from wet socks rubbing toes in your shoes.
sandals might work better.
bring a small plastic baggie you can close for your cell phone.
use a waterproof bag for cameras.
ponchos can help, umbrellas also if it rains straight done and no wind.
if the rain is light, might as well take in the water rides.
you are going to get wet anyway....
i do hope it is not a totally wet weekend for you when you go.
so many times weather issues are predicted and it never happens.
i hate hearing rain in the predictions for the time periods i plan to go to the parks.
i check weather predictions up to the day i leave for my trips