Warmest Fairbanks Weeks

Here's my take:

The  Weather Bureau/NWS era (1930-present) records are:

Warmest 7-day average maximum temperature (none overlapping weeks):

1. 87.9ºF June 20-26, 1991 & June 30-July 6, 1986
2. 87.4ºF June 14-20, 1969
3. 87.0ºF June 30-July 6, 1990
4. 86.7ºF July 24-30, 1954
5. 86.4ºF July 12-18, 1993
6.  86.1ºF July 19-25, 1968

Warmest 7-day average minimum temperature (none overlapping weeks):

1. 65.0ºF June 24-30, 2013
2. 62.0ºF July 11-17, 1975
3. 61.7ºF June 21-27, 1991
4. 61.1ºF July 4-10, 1975
5. 61.0ºF July 18-24, 1975
6. 60.9ºF June 25-July 1, 1983

The anomalies nature of the low temperatures in late June really stands out. Only 1.1ºF separate #2 from #6, while with high temperatures less than two degrees separate the top six.

The pre-Weather Bureau data from the Agricultural Farm (now called University Experimental Station) is plagued by data quality issues. There is zero doubt in my mind that the weekly average of 90.1ºF July 26-August 1, 1919 is bogus. No other location in Interior even had one day with a high of 90ºF, and this includes Nenana and Salcha. The average of 88.6ºF July 11-17, 1918 is less obviously bad, but is part of what look to be a host of anomalously warm summer temperatures recorded in 1911-1919 at the Ag Farm.