The weather in Florida is vastly different than here in the UK. Especially during hurricane season in the second half the year, the weather can be a bit out of control as we explained in our "Is Disney World For Me?" article. It gets really hot, but also rains quite frequently, almost like clockwork.
When it rains here in the UK, people either put on a coat or use an umbrella. In Florida, wearing a coat, especially when it's not winter, isn't feasible - it's way too warm. Using an umbrella also is not that feasible, because they have daily lightning storms, and that story wouldn't end well. It's also very annoying to have an umbrella blocking your view of something.
What option is left? Ponchos.
Here in the UK, ponchos just aren't common. I'm actually pretty sure I've never seen anyone wear one ever (outside of music festivals). If you ever get the pleasure of seeing someone in a poncho at home, they'll for sure stick out like a sore thumb. This is the reason why some brits don't embrace the poncho when they go abroad. They think they'll look as silly as they do here, over there. Luckily, that's really not the case. Ponchos are completely common, and dare I say - normal.