Personally I would have thought that protecting your skin from the sun would be preferable in a hot climate, I mean that's what Arab's do and they live in deserts
It depends.
Hot arid climates you want more covering to reduce sun exposure, but also loosely for some airflow.
In more hot humid climates, like near the ocean as they are now, you want as much skin to air contact for cooling as you can since sweating is less effective due to the higher air moisture preventing evaporative cooling. Plus your clothes get gross and sticky and heavier where ever they are touching your body.
That enforces his supernatural abilities, to be cool enough just by undoing the top button
