Critters braving the cold

Yesterday it was up in the low 70's but by last night it was down in the teens and sleeting. This morning it was around 15 with a wind chill factor of 1 (which means with the wind it felt like it was 1 degree F).
It still amazes me how some critters don't take shelter and stay right out in the weather and just take it. As mentioned in the other post the Common House Spider (Achaearanea tepidariorum) is one that braves the weather. I don't see how it keeps from freezing to death.
Below is a picture of one :