Cool air can't hold as much vapor as warm air. When you heat cool air the percent humidity goes down. In cooler climates the interior of heated buildings can become very dry and cause headaches and chronic dryness of the skin/nasal/throat passages. Any moisture introduced by washing, etc. is likely to condense in windows, walls etc. can cause mold/mildew problems and is not good for the structure. It also costs a lot of money to heat large (or poorly insulated) structures.

For all of these reasons, we like to dress warmer and use heavier bed covers and sleep in a cooler environment. Choice of fabrics and layers of clothes make a major difference. If you close the door to a bathroom when bathing you can keep in a lot of heat/humidity until you finish drying and put on a warm robe made of flannel, corduroy or terrycloth. You can live very comfortably in a high-60's interior.

Even outside, if there's not much wind and you're active -- you can be comfortable in the fifties or even high 40's without a jacket, especially in the sun. Less activity or more wind, and more clothes are needed.

But Uggs?? In 50/60's temps? Really!