Saturday, July 20, 2013

Maximum Minimums

Rick, thank you for the opportunity to contribute to your blog. Following the posts have been extremely educational as my focus is usually a little farther south. That being said, I would like to note the unusual low temperature that occurred recently. On Friday the low temperature in Anchorage was 61 degrees. This is the highest value on record for the station (Anchorage Forecast Office); although their period of record is only 15 years. The highest official reading for Anchorage was the 63 degree reading at Merrill Field in June 1953. Friday's 61 degree reading goes into the record books as the second warmest minimum temperature on record. Here is the list of the warmest low temperatures at the official Anchorage climate site:

1) 6/27/1953 63
2) 7/19/2013 61
3) 7/15/2003 61
4) 8/4/1999 61  
5) 8/15/1967 61
6) 6/26/1953 61

Pouring through the data generously provided by NCDC, the variability of low temperatures around a relatively small geographical area can be displayed cartographically. The two images below show the highest minimum temperature recorded for the stations around both Anchorage and Fairbanks. The length of record for stations varies tremendously. For Fairbanks, only stations with 10+ years of readings were included. For Anchorage, only station with 5+ years were used. As mentioned earlier, the 61 degree temperature for Anchorage Forecast Office is a station record and the 70 degree temperature for Fairbanks measured on June 25th is also a station record.


  1. Brian,

    Is it possible you could list the Fairbanks-area stations with record high minima above 70? When Fairbanks airport saw its low of 70 in June, we speculated that this was close to a state record (excluding some early 20th-century data that seems highly suspect). I also seem to recall reading someone, somewhere, claim that the Fairbanks record last month was Alaska's first reliable report of a 70-plus minimum... but perhaps this is not true. It would be interesting to examine the additional Fairbanks reports more closely.


  2. The data from the map were from the vast GHCN data repository. As wonderful as the data are, there are many types of errors in the system. I looked at the 70+ temps and here is what I came up with.

    College 5NM value of 72 had max and min temps transposed on the original, handwritten form. Correct value should be 68. Map value has been changed.

    College Observatory's value of 77 was property transcribed. The day before their 77 reading they had a 72 reading.

    University Experiment Station value of 77 had max and min temps transposed. Alternate value of 76 from 1915 is highly suspect as Rick has previously indicated. For the time being, I have changed the map value to 76. There is a 70 reading from 1983 that looks reasonable.

    1. Brian,

      Thanks. I enjoy digging into this kind of thing, and the question of the highest reliable minimum temperature is an interesting one. I looked at the 77 from College Observatory and I believe it (and the previous day's 72) is bogus, as the values are far different from the "official" Fairbanks record (the location of which I am unsure for 1948) and also the University Experiment Station. For all of the June days except June 17-19, the College Observatory minimum temperatures match the official record generally within a couple of degrees, and are not more than 5 degrees different. However, for June 17-19 the College Observatory values are far higher (the official record shows low temperatures of 54, 58, 55). It appears something went wrong with the thermometer or the measurements on those days.

      The Experiment Station report of 70 on July 11, 1983 also appears suspect, as the official record shows 60 and College Observatory shows 56. With a high temperature of only 76 that day, it seems implausible that the low was 70.

      So it's an interesting question whether it's possible to find, somewhere in the AK historical record, a minimum temperature report of 70-plus without any obvious problems. I'll be looking into this more when I have time.

  3. Sleeping on the concrete floor of my garage during the recent evening heat events to stay cool provoked a "why?" What goes in must eventually come out I suspect, and living off the north end of the Fairbanks airport surrounded by dark streets, trees, homes helps absorb the sun's radiant energy. No bubbling tar yet, but it does keep the evening warm after a hot day.

    We have an old hot roof house, so any solar eventually gets into the frame which stays warm through the night. But in winter our roof's R-value parallels any increase in snow depth. Then we're like warm voles living under feet of winter snow.