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°

Things become a little more dramatic when you look at the average maximum temperature. The trend since 2011 is pretty dramatic.

Finally, when you look at the number of hot days each year, we see the same alarming trend.

I think it’s fair to say that, here in Concord, CA, this has been the hottest summer in 30 years.

 

Here are the numbers I used today.

YEAR# of daysaverage max tempaverage 24-hour tempaverage min tempdays above 95°days above 100°days above 105°
1988998572582251
198999837057830
1990998471581350
199199826956712
19921068572581010
1993998572591651
1994998672581320
1995998472601650
19969987735926100
1997998673611130
199810684715923122
1999998269551251
200074*8471581652
2001998671572362
2002998571571472
2003998772582240
2004998672591440
2005998671571730
20069987725824126
2007998672571760
20089987725719104
20091068571572281
2010998470561331
2011998470561020
2012998570551620
2013998571571260
2014998672581550
20151068774601871
2016998873571780
20179990756030178

2017 is missing September 4 – Labor Day. KCCR did not have data for the following days in 2000: June 1-8, July 12-21, July 23-26, July 28-31.

 

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