A woman uses an umbrella for protection from the sun in the Juniata Park section of Philadelphia

It’s hot, and not just in Philadelphia. More than 100 million people across the U.S. have been under excessive heat alerts during the past week, per the Washington Post, as many locations see the temperature climb into triple digits.

The mercury hasn’t hit 100 degrees Fahrenheit in Philadelphia for a decade, according to historical data kept by the National Weather Service dating back to 1873.

But it could happen on Sunday.

Whether or not the thermometer registers that notable mark, it’ll definitely feel that way. What the NWS calls “maximum apparent temperatures” have been in the hundreds for days. The city declared a Heat Health Emergency on Thursday, which triggered some relief measures for residents.

A dozen branches of the Free Library were pressed into service as cooling centers, with extended hours — evenings and weekends! — and so people could take advantage of their free air conditioning. SEPTA chipped in by offering four cooling buses, set up on two corners in North Philadelphia, one in South Philadelphia, and on in West. The Philadelphia Corporation for the Aging also has a heatline you can call: 215-765-9040.

? Love Philly? Sign up for the free Billy Penn newsletter to get everything you need to know about Philadelphia, every day.

Saturday notched the high for this year so far, with 97°F recorded at Philadelphia International Airport. That didn’t beat the record for July 23, which was 101 degrees, set in 2011 — a year that holds the record for six different dates, per NWS.

(Note: The weather.gov website doesn’t allow linking directly to this data, instead providing tables generated on the fly, but if you want to go exploring yourself, you can start here.)

The most recent time Philly reached triple digits was in 2012. Since then, the mercury has maxed out at 96°, 97°, or 98°F.

This summer has been relatively mild in Philadelphia, with only a few spikes higher than 90 degrees, and none that lasted longer than two days — until this week. Per the College of Earth and Mineral Sciences at Penn State, here’s when they happened:

  • May 21-22 (91°, 95°)
  • May 31 (95°)
  • June 17 (95°)
  • July 12-14 (93°, 91°, 91°)
  • July 18-23 (94°, 93°, 95°, 96°, 96°, 97°)

Will that most recent stretch get topped off by a 100° or more? We’ll soon see.

In the heat, remember to check on older loved ones and neighbors. Find a sprayground or public pool using the map here, and keep these tips from the city in mind.

One Juniata Park resident parked himself under an open fire hydrant to escape the heat Credit: Kimberly Paynter / WHYY