Philadelphia, PA – Pennsylvania enters a dangerous stretch of summer heat beginning Saturday, as an Extreme Heat Watch remains in effect until 8 p.m. Tuesday, June 25, with peak conditions expected Monday in Philadelphia, where the high could hit 99°F.
According to the National Weather Service in Mount Holly, dangerously hot conditions will develop across eastern and southeastern Pennsylvania, with heat index values approaching 107°F. The alert includes Philadelphia, Montgomery, Chester, and Bucks Counties. Residents are urged to stay indoors during peak afternoon hours and avoid non-essential travel, especially on heavily exposed routes like I-95 and I-76, where surface temperatures may exceed 120°F.
By Saturday afternoon, the mercury climbs to 91°F under mostly sunny skies. Monday will be the most intense, reaching 99°F with a heat index over 105°F. Tuesday will stay hot, hovering near 99°F as well with little relief overnight as low temps remain in the upper 70s.
Health officials warn of increased risk of heat-related illness, particularly for seniors, children, and those without air conditioning. Drink fluids frequently, check on vulnerable neighbors, and never leave children or pets in parked cars — cabin temps can spike within minutes.
Expect another update if the heat watch upgrades to a warning or if additional air quality alerts are issued.
Five-Day Forecast for Philadelphia, PA
- Friday (June 20): High 86°F, mostly sunny, gusts up to 30 mph
- Saturday (June 21): High 91°F, mostly sunny
- Sunday (June 22): High 95°F, mostly sunny
- Monday (June 23): High 99°F, sunny, Extreme Heat Risk
- Tuesday (June 24): High 99°F, sunny, continued heat alert
