Except it hasn't. Average temperature in Phoenix is still running 1 deg. F below normal year-to-date.
Mean average annual temperature in Phoenix is 72.2 deg. F since 1895. Year-to-date it's 72.9. In 1974, the year of its big June heat wave, it was 73.1. The hottest year ever by average temperature was six years ago, when Phoenix averaged 77.3.
WaPo didn't check apparently, or simply omitted the inconvenient data.
Same with Reno, NV and Las Vegas, NV, both of which are mentioned in the story.
Reno is running 2.8 deg. F below normal year-to-date. Las Vegas is running 2.4 deg. F below normal.
El Paso is indeed setting records, but year-to-date its average temperature is still only 1.5 deg. F above normal. Annualized it would make the top ten warmest years ever, but the year is far from over.
Either way, WaPo is simply full of it, as usual.
It's also worth mentioning the special pleading going on.
WaPo cites the June 1974 Phoenix climatological records as proof that it's hotter now than during that heat wave:
Temperatures have averaged above 101 degrees in Phoenix over the past 17 days. That is significantly hotter than another record-setting heat wave, when the city surpassed 110 degrees on 18 consecutive days in 1974. During that stretch, temperatures averaged 96.5 degrees.
The June 1974 data is the same data The Weather Gods have now declared unreliable, but WaPo wants to have it both ways when the micro-average-comparisons are convenient, you know, like Hillary or Hunter, one law for me, another for thee:
Reliable observation times are not available prior to 1982.
