In Minnesota (where I live), the air temperatures can easily reach 30 below, and this does not include wind chill.  Since the head tends to lose heat more than any other part of the body, it is so important to keep the head warm - and this cap does exactly that.  Wool is a terrific insulator, and even when wet, it continues to provide insulating warmth.  Having a 100% wool cap means having a warm head covering in all kinds of weather.  I keep two of these, largely because of rapidly changing weather here in MN, one in the car, and one in the house. Yes, it will give you a "bad" hair day, but it will keep your head warm on the coldest days.  Great for walking, skiing, ice fishing, snow boarding, sledding, or any fall or winter activity.  The only thing better is a wool hood with the eyes, nose, and mouth open (I keep one of these handy for snowblowing).

konedog