As if that's not sweltering enough, tonight a "warm front" moves in, bringing a chance of thunderstorms and promising the two hottest days of the year so far.
Wednesday's forecast high of 96 for Philadelphia could challenge the record 97 set in 1888. With uncomfortable humidity pushing the heat index to about 100 degrees - and with an overnight low possibly above 80 in the city - an excessive heat warning has been issued by the National Weather Service for 11 a.m. Wednesday to 6 a.m. Thursday.
Thursday, though, could be more of the same - but with a chance of thunderstorms. The expected high of 95 has a tougher record to chase - 99, set in 1923.
Friday, Saturday and Sunday shouldn't be quite as uncomfortable, but highs are expected in the high 80s to low 90s.
High ozone levels can mean problems for children, the elderly, people with breathing problems, and anyone working or exercising outside.
An Ozone Action Day means that are asked to help reduce sources of the lung-irritating pollutant by carpooling or taking public transit, and refraining from mowing lawns and topping off gas tanks.
For more information about air quality, go to: www.aqpartners.state.pa.us.
Along with the excessive heat warning comes such familiar advice from the weather service as never leave people or pets in a parked car; check on relatives and neighbors, especially the elderly and or ill; drink plenty of fluids; stay out of the sun; stay in air-conditioning; and make sure pets are protected from the heat, with enough cool water.
For more on the forecast, go to http://go.philly.com/weather.
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.