[Yo-Yo]

Also, is it any surprise that nighttime temperatures typically keep dropping in many places until shortly after sunrise?

Is it any surprise that overall in the Northern Hemisphere that average temperatures continue to fall even after the Winter Solstice has occurred in December, and the amount of sunlight starts increasing?

[central_va]

Is it any surprise that overall in the Northern Hemisphere that average temperatures continue to fall even after the Winter Solstice has occurred in December, and the amount of sunlight starts increasing?

It takes awhile, in the fall, for the oceans in the northem hemisphere to cool. So by winter the oceans are cold and the temps keep going down.