Whats on your head?

[Scorpion Regent]

There was  hats thread that died out last June, hater than try to resurrect it I thought I would try broadening the topic.

What do you wear on your head? 
My go to hat is a Real Deal Brazil tarp hat.  Why? because there is something so infinitely freeing about a hat that is all ready broken in, you just wear and it works.
For deep cold I have a thick wool knit hat I will also wear in the rain because it stays warm even when wet and more often than not it doesn't soak through.  It keeps me warm and mostly dry.   
I have a old Seattle Sombrero that doesn't get much wear, it's a fine hat, but I don't spend time in constant rain.
Then there are my "unhats"   I have a several keffiyehs (some call them shemaghs) These are a true desert camping multi tool.   Cool during the day, warm at night, they cast good shade, they breathe, they soak and cool well and they can even cover your face during a sand storm.  The only thing it doesn't do well is rain.
I have countless bandannas which are also truly utilitarian.  It's a rare day I don't have one in my pocket and on a bad hair day I can quickly use one as a "do rag".
I have a handful of Buff's and their generic equivalents.  They are very versatile, but I tend to use them in conjunction with other things when it is really cold rather than wear them solo.

[SirVicaLot]

I hate having stuff on my head, so my options are limited to stuff that is very comfortable. Or I need it, because it is Winter 

In summer I either use a Buff or a very light cap from Outdoor Research. Both very light and comfortable for hours.