For a couple of years I was wearing either a straw or a black wool pork pie. This year I’ve been wearing a brown fedora. I’m thinking come Spring I’ll be sporting a trilby.
You?
A black Fedora that I don’t really wear much any more, I need a smaller brim (it makes me look too much like a Hasidic Jew, which is doubly disjointing since I’m Chinese-American)
A Panama straw hat (a real one) for the summer time
A cheap, coarse-weave straw hat for the summer time, for when I’m more casually dressed (shorts/t-shirt)
Baseball caps and skullcap wool winter caps don’t count, do they?
I have a number of baseball caps, of course. But depending on the circumstances, I have been known to sport a Tilley TM10, a fedora I found at an LA shop 30 years ago, or a Shepler’s Coburn cowboy hat.
I just made myself this snappy hat.
My two faves are a Dorfman Pacific Solarweave® desert hat and an “official” Red Sox cap. That Sox cap gets more comments than any item of clothing I’ve ever worn. I’m not even a fan, I just love the iconic-ness (iconic-ousity?) of that red B on the dark blue wool.
I haven’t worn a hat since I retired from the Navy, 28 years ago.
I wear a black knit cap in the winter. I want to look like Adebisi (the guy on the right) but I can’t quite pull it off. 
I’ve got a backwards Detroit Tigers hat from when they were in the World Series a couple years ago right now.
I will wear any hat that covers my ears in cold weather. I’m still trying to find one.
How about a deerstalker?
Ha! Johnny beat me to it. I occasionally wear a deerstalker, usually with an inverness. Sometimes one of those Irish caps, kind of like this, of which I have several, but I prefer a Resistol “natural” (rather than black) like this. Doesn’t work with a kilt or Inverness, or in the Corolla, but it’s my head cover of choice. I don’t like baseball caps, but I’ve a dozen or so that I’ll slip on if I’m dressed casually.
I’m not sure why I own so many hats, since I’m not much of a hat person.
This hat, but in shades of brown and tan rather than black and white.
No hat. I’ve got a huge head (normally wear a 7 7/8 hat size, at least) and thus have trouble finding hats. 
I’ve got a few driving caps; what we used to call Ivy League. I’ve also got a couple of nice Panama straw hats and two Panama Jack hats I bought in a beach wear shop. Given my skin cancer history, I wear hats pretty regularly.
Mainly a grotty, faded ol’ black baseball-style cap (one which was given out at a charity event by the company running the Skytower casino, so I’ve often had folks think I either work or gamble there. I do neither.) That’s worn all seasons (hence the accumulated fade-and-grottiness). In high summer, though, like right now, I wear a legionnaire’s style of cap, with the neck flap. The colour of choice at the moment is bright canary yellow.
A reversible bucket hat. White and blue paisley on one side, thin dark denim on the other. Good for bad hair days. I also got a houndstooth newsboy for for Christmas, but I haven’t worn it out much yet.
In the winter, I have a selection of toboggan hats to fit my mood when the weather gets cold enough.
Spring and autumn, usually it’s a nice, wool beret (colors to fit my mood as well).
Summer, something in straw or cloth with a brim. Like LouisB, a history of skin cancer is the reason there. I have a couple of boonie hats for hiking in cooler weather for the same reason.
I also have a collection of vintage ladies hats (you know, the kind that your mom or grandmother wore to church) that I wear once in a while when I’m dressed up.
I am occasionally wearing my ak kalpak - a nice Kyrgyz felt hat. It is surprisingly warm and comfortable. I find it really cool, too.
I wear an Akubra wide-brimmed hat when I’m outdoors (you have to in the sun here), and I’ve got a reproduction Boer War era British Pith Helmet that I sometimes wear to the range or out hunting. There’s no “Winter” here in Queensland, but I also have an ex-Russian army Ushanka that I got in the UK many years ago and that served me well through several UK and NZ winters.
What can I say? I like hats! 
Green plastic safety helmet, complete with huge ear defnders.