U.K. Warm Hat
Wool watch cap, Olive. Not polypro, not fleece, not black; an olive green wool watch cap is what you’re after. These are laughably cheap but awesome.
Also, acceptable is Hat, Cold Weather also known as the “Dangerous Brian” hat…incredibly dangerous I trust you’ll agree. It is being modeled on a mannequin head because no one else is willing to wear it. Undeniably warm, but...well just look at it.