From a Wall Street Journal story by Rachel Wolfe headlined “Midnight Dog Walks and 1 a.m. Shopping: The Heat Has People Living at Night”:

Call them heat vampires.

To cope with this summer’s record-breaking temperatures, people are going nocturnal. They are falling asleep in the wee hours or waking in them, resetting their biological clocks to take advantage of the comparative cool.

In the process, they are transforming ordinarily desolate night-scapes and compelling businesses to adjust their operations, creating a new after-dark economy that exists outside of clubs and partying. Couples are working out near midnight; families are running errands after the sun sets, and construction crews are starting work at 4 a.m.