Temperatures soared into the mid to upper 90s Saturday as the region continues to swelter.
By late afternoon, the heat index reached nearly 100 degrees in some places.
D.C. Mayor Muriel Bowser activated the city's heat emergency plan.
Humidity was slightly lower on Saturday, but muggy weather will intensify on Sunday, making it feel even hotter, Storm Team4 Meteorologist Lauryn Ricketts said.
A heat advisory is in effect Sunday from noon to 8 p.m. for parts of Southern Maryland and Northern Virginia. See all weather alerts here.
The National Parks Service said the Billy Goat Trail A in C&O Canal Park near Great Falls will be closed Sunday and Monday due to the heat.
D.C. got a short break from daily highs at or above 90° Thursday, breaking a 20-day heatwave. It was one day short of tying the region's all-time record.
The upcoming workweek, however, will not bring a reprieve. Monday will still be hot and humid with a heat index around 103-108°.
Tuesday will be partly sunny, muggy and dangerously hot again with a heat index of 102-107°.
There is a chance for storms Sunday, Monday and Tuesday.
You can still enjoy the summer sun if you're proactive to prevent dehydration. With the heat index getting above 100° for the next several days, please remember to add an extra glass of water to each meal. Don't wait until you feel thirsty.
Remember to bring pets inside and check on your neighbors.
Stay with Storm Team4 for the latest weather forecast.