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September 03, 2023

Philly braces for a record-breaking heat wave, just as the summer season ends

City schools are already planning to close early as temperatures climb into the mid-90s this week

Weather Heat
Philadelphia heat wave THOM CARROLL/for PhillyVoice

The Philadelphia region is expected to see temperatures in the mid-90s throughout the week in what could be the longest heat wave of the year so far.

As summer winds down, the heat is picking up. Starting Sunday, the Philadelphia region is expected to see temperatures break into the 90s and stay high throughout most of the week. The forecasted heat wave could be the longest hot spell of the year thus far.

Traditionally, Labor Day weekend marks the unofficial end of the summer season, as students get ready to go back to school and the last of the city's public pools close for the summer. But September can still see summer-like heat, and this year is no exception. Temperatures in Philly are expected to hit 93 on Sunday and then jump to 96 for Labor Day on Monday.

Dozens of Philadelphia public schools are already planning early dismissals this week due to the heat. Schools will close early from Tuesday September 5 through Friday September 7, giving students a little back-to-school relief during an already-shortened post-holiday school week.

The 90-degree-plus hot spell could last until Friday, according to local weather forecasts. Monday's high of 96 is expected to hold steady through Tuesday, followed by 97-degree days on Wednesday and Thursday. Things should start to cool off on Friday, as temperatures drop down to 92 before returning to the mid-80s on Saturday.

If forecasts play out as predicted, this week will mark the longest heat wave of the year so far. The hot spell comes at the end of a summer season that saw plenty of hot days, but only one city-declared heat health emergency. Philly officials declared a three-day heat emergency starting July 26 as temperatures pushed into the mid-90s with humidity making it feel even hotter. During an official heat health emergency, the city of Philadelphia activates several cooling centers across the city, extends public library hours and opens up its heatline phone service for residents experiencing adverse effects of excessive heat. The city will also extend its homeless outreach services and temporarily halt utility shutoffs.

As of Sunday morning, the city has not declared a heat health emergency for this week's hot spell.

For many, the heat wave may be conveniently timed. The four-day Labor Day Weekend is traditionally when many people celebrate the unofficial end of the summer season with one last pool party, trip down to the Jersey Shore or dip in the local swimming hole. While the city’s public pools offered Philadelphians respite from the heat this summer, those pools have already begun shutting down for the season, with the last of them expected to be drained by the end of this week.

Of course, excessive heat is not always fun-and-games for city residents, even if it is a holiday weekend. Such hot spells, which are expected to become more common as climate change continues to push global temperatures higher, can create dangerous conditions for many throughout the city. This is especially true for vulnerable populations like children, the elderly, those experiencing homelessness and anyone without air conditioning in their homes. 

Extreme heat can also cause or exacerbate health issues. Heat exhaustion and dehydration are common health risks posed by higher temperatures. Recent studies have shown a direct correlation between hot weather and an increase in hospital visits. 

Exposure to high heat is also known to stress the cardiovascular system and make the heart work harder, increasing the risk of heart attack, irregular heartbeat and heart failure. When combined with other harsh conditions – such as the wildfire smoke from Canadian fires that blanketed the city earlier this summer – the health risks posed by heat can be even higher

In the event that the city does declare a heat health emergency, residents experiencing discomfort or health risks on account of the hot weather are encouraged to call the city's heatline at (215) 765-9040 or seek refuge in one of the city's cooling centers.