= new reply since forum marked as read
Though I think he should have chosen a different color in case anyone viewing it from a distance might get the wrong idea... 
It should be BLUE. 
Btw, tonight Bill Maher wore a red one exactly like the one above. He ranted about ill-advised manned flights to Mars and how we need to save this planet instead of foolishly spending billions on trying to inhabit Mars. My hubs and I agree 100%. People who don't agree don't fully comprehend all the facts.
(Full disclosure, my hubs is a NASA physicist.)
We need to work to protect the planet we have rather than spending trillions engaging in crazy and ill advised pipe dreams. 
As for the hat, blue would be fine, or green. As long as it isn't red like those offensive Trump hats, any color's fine with me... 