Harmony Simon, a postal worker, visiting Martine Combe in Aix-les-Bains in July.

A delivery in Wilmington, N.C., this month. Heat is linked to hundreds of workplace deaths each year, but labor groups say the true toll is unknown because heat-related illnesses are not properly tracked or reported.

Krumme Lanke lake on a hot day in Berlin this summer.

Officers responded to Starlight Park, where they found Darrell Harris, 17, mortally wounded with gunshot wounds to the head and arm.

The temperature on Tuesday reached 99 degrees in Central Park, where the city’s official weather station is. A thermometer there last reached that temperature in 2012.

In Mountain House, Calif., temperatures yesterday reached 107 degrees, the start of what is expected to be a weeklong heatwave. High temperatures in the region average 95 degrees in a typical July.

Hansa Ahir, left, who salvages recyclable waste for a living in Ahmedabad, India, bought an insurance policy to cover her income on days when heat makes it dangerous to work.