While the coolest valley spots are now regularly dropping below freezing on clear nights, of the long-term climate sites in the Fairbanks area only Eielson AFB has reached 32F. At North Pole, the low so far has been 33F, which makes this now the latest "first freeze" of record there (data since 1969). Both the Experimental Station and College Observatory have had multiple days with lows in the mid 30s, but again no freeze. For both these sites the median date for the first freeze is around Sept 1. The median date for the first at the airport is approaching, but no sign yet of any freeze outside of the low spots.
The last freeze at Eagle Summit, 3650' MSL, was May 14th