Heat indices could reach 108 degrees in the Radnor and Haverford area on Wednesday, July 15, prompting the National Weather Service to issue an Extreme Heat Watch for the entire Philadelphia metro region, including Delaware County.
The watch follows a multi-day heat wave in early July that killed seven people in Philadelphia and at least 44 nationally, according to USA Today.
NWS meteorologist Erich Hoeflich, of the Mount Holly, N.J., regional office, said Monday that "Wednesday will be the hottest day of the stretch" and that temperatures could "tag the century mark again."
The NWS forecast calls for a high near 100 on Wednesday with west winds gusting up to 20 mph. Heat indices are expected to range from 100 to 108 degrees. Above-normal temperatures will continue through at least Friday, July 17, with highs in the upper 80s to mid-90s.
AccuWeather senior meteorologist Dan Pydynowski said the event will not be as long or intense as the early July heat wave but urged anyone who must be outside to take frequent breaks, wear light-colored clothing and stay hydrated. He recommended staying in air-conditioned spaces during peak hours of 10 a.m. to 5 p.m.
Local cooling centers
Delaware County's 2026 Heat Plan lists both Radnor Memorial Library (114 W. Wayne Ave., Wayne) and Haverford Township Free Library (1601 Darby Rd., Havertown) as designated cooling sites during heat emergencies. Residents should call ahead to confirm availability on Wednesday.
The Wayne Senior Center at 108 Station Road is also available as a cooling site, open Monday through Friday, 8:30 a.m. to 4 p.m. The County Office of Services for the Aging is distributing free fans to seniors at all COSA-funded senior centers. Seniors can call COSA at (610) 490-1300.
Whether Delaware County will formally activate a Code Red alert for Wednesday, July 15, has not been confirmed as of Monday, July 14. Residents should check delcopa.gov or call the county Health Department's Wellness Line for updates.
Safety tips from the county Heat Plan
The plan advises drinking one cup of water every 15 to 20 minutes when working in the heat, totaling 24 to 32 ounces per hour. It warns against exceeding 48 ounces per hour, which can cause a dangerous drop in blood salt levels.
Never leave children or pets in vehicles. On an 85-degree day, a car's interior can reach 102 degrees in 10 minutes.
Resources
The Delaware County Health Department Wellness Line is available 24/7 at (484) 276-2100 or [email protected]. Residents 60 and older who need additional assistance can contact COSA's Information and Assistance service at (610) 490-1300.
