As I wrote about last winter, at 65 degrees north latitude there is no appreciable solar heating in the weeks around winter solstice, which means there is no change in solar heating that would cause one to think the temperature would drop overnight. The lack of auto traffic overnight can result in thinning of ice fog (though that's not a hard and fast rule), which can allow for surface cooling if the ice fog thins enough. In general though, with a gradually warming airmass, no clouds and no wind, Interior Alaska valley temperatures in late December should be nearly steady, eventually rising a bit.
|Courtesy of IARC|
The 2-day plot of the 2-meter temperatures from the sensor near Smith Lake on the UAF Campus shows all this nicely: there is no sign of any afternoon solar related temperature increase and since about 4pm Thursday there is has been minimal temperature variaiton.
Low temperatures since Thursday afternoon include:
North Pole: -51 (thru 11pm Thursday)
Woodsmoke PWS: -49F (near North Pole)
Fort Wainwright: -48F
Fairbanks Airport: -47F
Golstream Creek: -47F
Eielson AFB: -46F
UAF West Ridge: -38F
College Hills: -30F