She probably knows where all the warmer places are when she tires of keeping watch.
I bet she does. She also probably knows where to mooch scraps. Kitty looks pretty healthy.
My sister lives in Minnesota and has 3 outdoor cats. As everyone knows the winters in Minnesota are brutal. She has a doghouse with heated blankets in it for the cats and she feeds them warm food every day. They also sleep in a basement window well where the warm air from the house seeps out through the window.