Monthly Archives: September 2017

image how hot?

This weekend, the San Francisco Bay Area is having an historic heat wave. In the City, temperatures reached 106°F, while out here in Concord, we have seen 116°. On September 2, Concord was hotter than Bangkok and Death Valley! Since Weather Underground has great data, I thought I’d take a look at the trend.

First, here at our house: We have a weather station in the backyard that reports data to Weather Underground. It tells us the following about the period from Memorial Day through today this year:

  • 96° – the average maximum temperature
  • 77° – the average of the 24-hour mean temperatures
  • 56 – the number days where the maximum temperature exceeded 95°
  • 33 – the number days where the maximum temperature exceeded 100°
  • 24 – the number of days where the maximum temperature exceeded 105°

Yes, it’s been hot, but has this year been hotter than others? I looked at the historical data for Buchanan Airfield (KCCR) for the past 30 years and I came up with a few interesting charts. (Click on these to see a bigger version.) Traditionally, summer runs from Memorial Day through Labor Day: that’s the period covered in these graphs.

The “mean temperature”, which is the overall temperature in a day, was at an all-time high this year. From 1988-2014, the range was 69° to 72°. 2017 has been higher than that: the average mean temperature has been 75°