Warm Weather Frequency

With the Tanana Valley Fair in full swing and a bout of cooler weather the last few days, it reminds me of how quickly temperatures drop off in Interior Alaska, climatologically speaking.

Here is a plot of the frequnecy, by week, of daily high temperatures of 75F or warmer (Data 1905-2010). There are a couple of interesting things here. First, from late May to late June there is a basically linear increase in the frequency, then a plateau the first half of July. The decline is not quite so linear from mid July to early August, but close. Thereafter days with high temperatures 75º or warmer become increasingly unusual. The latest date with a temperature so warm is Sept 21, 1995 during a spectacular chinook.