(CBS News) NEW YORK - Day after sweltering day, from the Gateway Arch in St. Louis, to Chicago's lakefront, to Times Square in New York City, triple-digit temperatures just won't quit.
Two-hundred-thirty-eight cities have set all-time highs in the last 30 days, according to the National Oceanic and Atmospheric Administration (NOAA).
And weather historian Chris Burt says the heat wave that started last month is one for the ages. He says June "will probably go into the record books" as having more all-time high record temperatures set than at any time since June of 1936.
Burt says the air mass responsible for the heat wave started in Mexico, worked its way into the Rockies, tracked east to the Mid-Atlantic, then retreated, settling over the Midwest.
"Once this pattern sets up, it can become stagnant," he points out.
The prolonged heat has taken its toll on infrastructure.
Just outside Washington, D.C., where temperatures topped 95 degrees for the ninth straight day, a Metro car derailed Friday. Fifty-five people were evacuated, but no one was injured.
A road near Madison, Wis., needed repairs after buckling from the intense heat.
The National Weather Service issued heat warnings for 25 states Friday, with more expected Saturday.
So far, the deaths of 13 people have been blamed on the extreme temperatures.
Inside the control room at Con Edison, the New York City utility that provides power to 9 million people, they're bracing for another day with the mercury approaching 100 degrees.
"The heat always gives us a challenge. ... We expect scattered outages," observed Con Ed spokesperson Michael Clendenin.
The good news for Con Ed: Power consumption in the Big Apple declines bout 15 percent on weekends since many residents leave town.
Also, the heat is expected to break sometime Sunday for most areas still under its spell.