If it is your uniform, then wear it with pride !
We (A regional) can leave jackets in the crew room if it is warm. Never found my hat too hot, but ties can get a bit that way on the ground in a cockpit before APU/engine start.
Footballers say "If you can't be a footballer, at least try to look like one ! "
Remember attitude + attitude (aircrafts + pilots) make the flight !