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In-Depth: Utah's Summer of extremes actually continued a trend

Posted at 7:41 PM, Sep 03, 2021
and last updated 2021-09-03 21:41:35-04

SALT LAKE CITY — Utah is in a drought while experiencing record rainfall and destructive flooding in places.

Utah had the hottest summer on record (tied with 2017) but August was over 2 degrees below the mean when averaged for the month.

Utah had one of it's best winter inversion seasons in a decade, but August was the second worst month for particulate air pollution in the last decade because of wildfire smoke.

Climate scientists and economists for power companies like another way to measure exactly how hot a day, month or season was.

They are called "Cooling Degree Days" or CDD.

CDD is a way of looking at how much energy use will go up for people to cool down when it's hotter than average.

How does it work? Imagine the perfect temperature for your electricity bill is 65 degrees as a daily average. Above that and you will start turning on the AC at the hot points in the day. Below that and you start turning on the heat at night or in the morning.

If a day's average temperature is 66, hat is one CDD. If it's 75, that's ten CDD.

July is the hottest month. When you add up all 31 days, it averages 500 CDD. July 2021 added up to 649.

The overall CDD for the meteorological summer 2021 (June, July and August) was 1491. That's the highest total since record keeping started in 1875.

The hottest three summers have all been in the last 7 years, with the rolling ten year average for summer CDD up from below 800 at the turn of the 20th century to above 1300 now.