The Maine Warden's hat with flaps that reach all the way under your chin is an incredibly warm design for its weight and bulk. You can adjust it to cover the top of your head, add the ears or the sides of your face as you wish. I keep this hat in my pack for the coldest days.
ProsDurable, Great Value, Comfortable, warm, light
I have an version of this hat with shorter ear flaps. Very good product. Warm, windproof, waterproof, comfortable, light, compact. Only on the coldest days of last winter did I wish a warmer hat. The only thing that could be improved upon is to make them with longer bills for better protection from snow and late fall rain.
I had a hat like somewhat like this one winter in Kodiak. Been looking for another one ever since. This hat is good, stays on in the wind and keeps the ears warm. Only drawback is the brim could be a little longer to keep the snow out of my eyes.