I was driving up near Finlayson this morning. I noticed a temperature contrast that was worth noting. Driving on I-35 the temperature was about 1 below in Forest Lake.
As I continued driving north the temperature was cooling off. By the time I got to the Finlayson exit, the temperature was 6 below. As I traveled west on Hwy 18 the road took a few dips. The temperature in the bottom of the dips was 14 below. As I came out of the dips the temperature rebounded to between 6 below and 9 below.
This is a good lesson when locating hives. Avoid low spots. Cold air runs like water. If a hive is in a lower spot and is surrounded by trees and brush. The vegetation will hold the cold air. If the brush was cut in a fashion that forms paths. The cold air can possibly leave and not settle in on frosty mornings.