In honor of the wonderful history of climate data from this site, here's a quick look at summer temperatures since 1911. A few of the years are missing rather a lot of data (up to a month's worth in the 3-month period), but I've included those years in the chart anyway.
Just like at many other long-term climate observing sites, there's a more pronounced long-term warming trend in daily low temperatures than in daily high temperatures, and in fact there's essentially no trend in the high temperatures.
One feature of the chart that stands out is the rash of very high temperatures in 1915-1919, including 95°F in June 1915 and 99°F in July 1919. Of course the June 1915 heat wave was the one that produced 100°F at Fort Yukon, and the Fairbanks observer recorded a daily minimum temperature of 76°F in the same event.
If this 76°F low temperature were believable, it would almost certainly be an all-time state record for highest daily minimum, and at first glance it might seem plausible because of the magnitude of the heat wave and the date on the calendar: June 26, a suitable date for very high overnight temperatures. Unfortunately, however, the report appears to be incorrect, because marble-sized hail and 0.18" of rain were observed on the same day, and these surely would have brought the temperature to well below 76°F. The relevant portion of the June COOP form is copied below.
As an aside, Rick Thoman has previously shown that the 99°F in 1919 is also wrong; the all-time heat record for Fairbanks stands at 96°F, observed in 1969.