We live in Las Vegas where rain is almost a fictional character. My kids love, love, love playing in the rain and they even get excited to watch the rain through the window. Depending on where you live, you may dread a rainy day, but we love them. It helps when it rains all of 10 days a year give or take.
So when it rains we go outside and play in it. And as luck would have it, we got rain during the day on Fourth of July. It was awesome! Instead of the temperature being 108, it was in the 70's and since it's the desert, it was only a little sprinkle, perfect for some outdoor play.
This is how "wet" they were after 1 hour of playing in the rain.
Daddy relaxing in the rain