Any discussion about clothing for cold conditions will say cotton is a poor choice. A former member of the Brigade used to say, “you are better off naked in the cold and wet than wearing cotton.” I’ve often thought about the better off naked comment and wondered if there was a way to demonstrate it without actually going naked in winter. I decided to test it by filling one gallon jugs with hot water all at the same starting temperature. Each jug was “dressed” in different materials. Cotton, wool, sythentics, etc. and one was left “naked.” I then used the shower in the tub to wet all of them down and turned a fan on them. I then proceeded to measure the temperature of the water in each jug every five minutes for an hour. The results can be found in the file download below. Notice the jug dressed in cotton cooled off faster than the naked jug and jugs dressed in more cold weather friendly materials such as wool and synthetics fared much better.
Granted a naked human body would respond differently than a jug of water but the chart does demonstrate why you shouldn’t wear cotton in the winter. Cotton soaks up water very easily and then holds onto it. Water conducts heat away from your body much faster than still air and the evaporative effect just adds to the heat loss. Synthetic materials tend to repel water and thus don’t get as wet and wool, although it gets wet, retains its insulating value. by maintaining dead air space in its fibers. Notice even a cotton blend is better than pure cotton.