This. I have worn my hat on walkarounds simply for the heat saved on my head. Having a beanie available might solve this issue but in the spur of the operation, the hat comes in handy.
I wear mine if it's raining. That giant hat acts like an umbrella.
Not really, it just funnels it all down the back of your shirt. The porous vest gives you just enough protection to not feel it until you sit back in your seat.