There are a number of ways to define the informal beginning of Winter. Previous posts have looked at the date of the first freeze and the first measurable snowfall. In this post, I look at the first day where the high temperature is at or below freezing. For Fairbanks, the average date for the first sub-freezing high is October 9th. So far their coldest max temperature has been 34 on 9/22. For Anchorage the average date is October 27th. On the map, only stations with at least 15 years were used and the years were not required to be consecutive nor contemporary. The earliest average date for any station is for Barrow (September 2nd) and the latest average date belongs to Craig (December 24th).
As for coming up with a proxy measure for the beginning of Winter in Alaska, any thoughts on the different criteria are welcome. Here are some thoughts. 1) First snow, 2) First low temperature below 20, 3) Seven or more days with 1"+ snow on the ground, 4) First day with high temp below freezing, 5) Seven or more days with low temperature below freezing, 6) ..... I intend to write a paper on the relative dates of the seasons for Alaska. Very little research has been done on the subject.