Our first day at Disney Worlds' Magic Kingdom was on a day that set a record in Orlando for the most rain on that day. We had over 1.7 inches. It rained steadily with occasional downpours.We only had 4 days so we had to make the best of it!
I do have a few tips if you are going on a rainy day.
1) Attitude is everything. You will get on any ride without waiting if it's pouring. Riding on Dumbo twice in a row with my granddaughter was a good as it gets, regardless of the weather. No wait, just get back on after the ride ends.
2)There are enough inside attractions that you can get out of the rain,especially if it pours.
3) Plastic ponchos are highly overrated. While the Disney ones (now $ 8.50) will work in a slight rain, in pouring rain, they don't get the job done.
The best solution is a waterproof-breathable jacket with a hood, Gore-tex, Hyvent etc. all work pretty well. With a hood you can walk around and stay dry in even pouring rain. Well worth the investment. But DON'T expect to be able to buy anything like a Gore-tex jacket at Disney. It seems to be Ponchos or nothing.
4) Sandals are the way to go in the rain. Puddles are a target, not a problem. That said, if you don't like sandals, like me, synthetic socks in running shoes work great. Your feet are wet, but the synthetic socks won't cause blisters. Stay away from cotton socks and you'll be fine.
5) Same is true for shirts. Synthetic (UnderArmour, Columbia, etc )workout shirts keep you dry under your jacket as you move around.
6) Shorts are the only option for pants. You choose the material and length. Wet legs dry fast once you're under cover and are warmer than wet pants in the pouring rain.
7) Umbrellas finish second to ponchos, they're bulky, hard to deal with when you go inside, and in hard or wind driven rain, pretty much useless. Leave the umbrella at home.
8) Smile and learn from the kids, rain is for laughing, and puddles are for splashing. You're at Disney World! You can wait for the sun or learn to dance in the rain. My granddaughter taught me to dance in the rain. Thanks Mia!