Thursday, September 19, 2013

A Short But Intense Growing Season

With the 0.6" of snow that fell in Fairbanks on Wednesday, we can calculate the length of the snow-free period since the last Spring snow. 123 snow-free days occurred between the May 17th snow and the September 18th snow. During those 123 days, over 1,300 growing degree days (GDD) accumulated in Fairbanks. A GDD is tabulated for every degree that the daily average temperature is above 50°F. For example, a day with a daily average temperature of 55°F records 5 GDD for that day.

The 2013 value is the second most on record for the snow-free period. Only 2004 had more GDDs. What is remarkable is that the accumulated GDDs occurred during one of the shortest snow-free periods on record. Looking at it on a per snow-free day, 2013 was far and away the largest value for any year on record.


  1. Brian,

    Very, very nice analysis - well done. One of those that makes you think, "Why didn't I think of that?" Fascinating, indeed!


    1. Thanks Richard. Usually the Growing Season is bounded by 32, 30, or 28 degree temperatures but I thought that the snow-free period would be an interesting proxy for the Growing Season. I can't speak for Fairbanks but it was a good year to have a garden here in Anchorage.

  2. Nature knows what's best. I've shaken and thrown my bag of bones, and they tell me we're in for another long winter in Alaska. The intense growing season was for the birds, insects, plants, and their consumers to carry them through the coming cold.

    CU in the Spring to see if I'm mostly correct. I hear crow tastes pretty good should that be my fare.