Rick Thoman has been closely following the lenthening growing season in the Interior and across Alaska.
Based on 109 years of weather information recorded at the Fairbanks Experiment Farm, Thoman said this past summer was the farm's third-longest growing season. Its weather station recorded 129 frost-free days. The fall frost arrived on Sept. 22.
Thoman is a climate scientist with the Alaska Center for Climate Assessment and Policy at the University of Alaska Fairbanks.
As Thoman's graph indicates, the growing season at the farm has lengthened by three weeks over the past 49 years, from 1970 to 2019. Seven of the 10 longest growing seasons have occurred since 1990 and the 10 shortest seasons were before 1970.
This past summer also recorded the second highest May-September growing degree day total (GDD), a measure of "accumulated warmth." Some crops require a specific total in order to mature. The growing degree day total in 2004 was slightly higher than in 2019.
Thoman said another UAF scientist is looking at whether changes in accumulated warmth are actually more significant than changes in the growing season length. The issue was referenced in a publication that Thoman and John Walsh published in August, "Alaska's Changing Environment."