Thanks everyone!
Tom, I was hunting in the coast range mountains, and the temperature would vary between too cold for what you see me wearing in the picture, to where I would feel too hot in a cotton tee shirt. It would depend a lot on the fog. At the time I shot the deer, the fog was in, it was cold and damp, and I was happy I had the jacket. Also happy because the cold made it ideal conditions to hang the deer for a while.