Summer temperatures in the U.S. have been rising on average 0.4 degrees F per decade since 1970, or about 2 degrees F overall, but the Southwest and West regions have borne the brunt of those increases, according to an analysis by Climate Central.
In the Southwest, temperatures have risen an average of 0.6 degrees per decade, with a few localized areas warming as much as 0.9 degrees per decade. In the West, some parts of California and Nevada have warmed 1.32 degrees F per decade, or more than 5 degrees total since 1970.
On the other end of the spectrum, the Upper Midwest has seen the lowest increases. Temperatures in that region have increased only 0.1 degree F per decade on average.
The National Climate Assessment, released last month, found that annual average temperatures in the U.S. could increase by 10 degrees F before the end of the century if the rate of greenhouse gas emissions doesn’t slow.