What should I wear when I visit the UAE/Expo 2020 Dubai?

you need light clothing and you will NOT need a jumper the coolest ever was 16 degrees and theses types of temperatures are in the early morning. during the day its around 22 to 26 deageses  

cotton clothing to breath.. .. dont show too much skin..

You can wear what ever you want, unless it's beach or strand wear. I would recommend loose fitting clothes made of natural materials. But, if you want to wear Jeans and t-Shirt, it's okay, like every other clothes as well.

Clothes are a good idea.

Suggest you check the expected weather for the day and dress accordingly.

Showing lots of skin is not in good taste and has a risk of sun burn. The event is six months long . Did you expect the same weather everyday?

A burka would be appropriate.

A bullet proof body suit!