Living in the Northland for any length of time you start to pick up on accepted weather-related norms:  things like "colder by the lake" and "it usually doesn't snow when it's cold".  Usually these accepted facts have a variety of science (and sometimes geography) to back them up.

One of those factoids that gets thrown around a lot is the "morning dip" - the observance that temperatures usually dip just after sunrise.  While that dip occurs during all seasons, it seems to be noticed the most in the winter when a cold overnight suddenly gets even more brutal after the sun comes up.

The observation isn't without science to back it up.  I found a good explanation of the phenomenon from two professors in the Department of Atmospheric and Oceanic Sciences at UW-Madison - that run a weather-related website.  To summarize the science, the Earth has infrared energy that solar energy from the sun counter-balances.  In the time frame that happens right after the sun comes up there isn't enough solar energy to burn off the infrared energy.