For a first post, I thought I would highlight the extraordinary jump from unusually cold spring conditions to unusually warm summer conditions in Fairbanks this year. I imagine the pace of change might have been dizzying even for locals used to extreme weather variations. In a "typical" year (which rarely exists, of course), the average temperature would increase by about 21° F from the "spring" average (which I'm calling April and May) to early-mid summer (June 1 - July 15). This year the temperature increase was over 34° F, and by far the highest in the Weather Bureau/NWS era (1930-present). The chart below shows the annual values, and 2013 really stands out; the previous record increase was 28.5° F in 1986.
The 2013 change is especially unusual in light of 2010-2012, which saw a much more gentle transition from spring to summer. The seasonal temperature increase in 2010 was the smallest in the record, only 14.2° F.
The remarkable change this year was created by the sequence of the coldest April-May period on record in Fairbanks (except for 1911), followed by one of the warmest early summer periods on record. Among the unusual events was the latest first day with mean daily temperature above freezing (April 24), and then less than two months later there were 6 consecutive days with a high temperature of 86°F or above (June 15-20) which has only happened once before in 1918.
So in summary, the swing from one temperature extreme to the other since spring in Fairbanks has no precedent in the modern era. From a meteorological standpoint, the reversal in extremes seems to be related to persistent high-latitude blocking around the northern hemisphere, which has created many persistent and extreme anomalies in different locations. Another factor seems to be the evolution of sea surface temperatures in the North Pacific in recent months, which seem to have favored cold in the spring and warmth in the summer. But that's a subject for another post...