An umbrella hat is like wearing a hat that has an umbrella on top of it, so that when it is rainy or sunny outside, you can wear it to protect your head from getting wet or too hot. It is a silly accessory that people wear for fun or to show off their style. But remember, it might not keep you as dry as a regular umbrella or protect you as much from the sun, so it is not always the best choice in extreme weather conditions.