Extreme heat streaks on the rise in Philadelphia
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Heat streaks in Philadelphia are getting more common each year on average compared to 1970, a new analysis finds.
Why it matters: Prolonged heat — as Philly and much of the U.S. has experienced this summer — is particularly hazardous to human health.
- Plus: Multi-day heat streaks are also challenging for power grid operators, given all the energy-intensive A/C use.
By the numbers: Philly averaged five extreme heat streaks between 2020-24 — two more than during the 1970s, per a report from Climate Central, a climate research group.
How it works: Climate Central defines an "extreme heat streak" as three or more days in a row with maximum temperatures over the 90th percentile of a given location's daily max temperatures during the 1991-2020 period.
- For Philly, that threshold is 89 degrees, per Climate Central.
🌡 The latest: Philadelphia is in the midst of a hot and humid streak, with temps or the heat index clocking in above 90 since last Friday
- Wednesday's temps are pegged to hit the upper 90s and remain in the high 80s with a chance of showers on Thursday, per NWS.
- Yes, but: Relief is coming. Temps are forecast to dip into the mid-70s on Friday and lower 80s on Saturday.
Zoom out: The average number of extreme heat streaks rose in 80% of the 247 U.S. cities analyzed by Climate Central.
- But a few places, like Myrtle Beach, South Carolina, and Sarasota, Florida, now have fewer heat streaks compared to 1970.
Between the lines: Climate change is making extreme heat more intense and more frequent, studies have shown.
- Many urban neighborhoods — including those in Philly — suffer from the "urban heat island" phenomenon, where buildings, roads and other structures trap heat, making it even hotter.