A hyperthermia alert and a heat advisory were issued Monday as one of the hottest weeks of the year got started.
By 11:45 a.m., D.C. officials say the heat index had reached 96 degrees, prompting an alert to be activated.
The heat advisory is in effect for parts of the D.C. area including the district, Arlington and Falls Church until 7 p.m. Tuesday.
Authorities recommend drinking plenty of water, wearing loose and lightweight clothing, staying in indoor and air-conditioned buildings and avoiding strenuous outdoor activities to avoid injury or illness.
Symptoms of hyperthermia, which occurs when the body absorbs more heat than it can dissipate, include hot and dry skin, lack of sweating and, in some cases, nausea, vomiting, fainting and dizziness.