If we define the growing season as the period with continuous temperatures above either 27°F or 28°F (under the assumption that anything warmer may not be a killing freeze), then Fairbanks has already broken the record for longest such period on record: for a threshold of 27°F, it's now 170 days and counting. Here's some context on historical values in the Fairbanks climate record:
http://ak-wx.blogspot.com/2015/04/growing-season-length.html
The map below, courtesy of xmACIS, shows the season-to-date lowest temperature; several other locations around Fairbanks and in the hills have also failed to see a significant freeze thus far. (The 19°F in the bottom right is from the Salcha RAWS.)
Looking farther afield in the interior, cold has been very scarce elsewhere too. Note the amazingly warm lowest temperature of 25°F at the Chalkyitsik RAWS; this site normally dips close to 0°F by this date. A temperature below 25°F is normally observed by the end of August at this spot.
The abnormal warmth in Fairbanks is a continuation of the anomaly that persisted throughout most of the summer and was particularly noticeable in high daily minimum temperatures owing to high humidity. The same trend is still very much in evidence: it's still much more humid than normal. Fairbanks has only had a single day so far this autumn with a sub-freezing average dewpoint, compared with a normal dewpoint of about 25°F for this date. Even at this time of year, high humidity reduces the rate of cooling by radiational energy loss; although of course the recent warmth is more easily explained simply by the lack of cold air masses over interior Alaska.
