DC's Heat Advisory is in effect, this is what it means

From the website of Homeland Security and Emergency Management Agency

Heat Emergency Information

When the temperature or heat index in the District reaches 95 degrees, District Government, through the Department of Human Services (DHS) and the Homeland Security and Emergency Management Agency (HSEMA), will implement the Heat Emergency Plan and activate cooling centers for residents to seek relief. Residents and visitors should take extra steps to beat the heat by staying in the shade or air-conditioning, drinking plenty of water and visiting a cooling center. Periods of high heat and humidity can cause medical problems such as heat exhaustion and stroke.

DC Recreation CentersDC Public Libraries and Senior Wellness Centers are open to the public and places you can go to beat the heat. For more information on where to go, call 311 or text 311 to 32311. 

The Department of General Services (DGS) advises caution when using recreational services throughout the District during heat emergency. For more information on our field safety guidelines, click here.

Interactive map: Click here for the 2019 cooling center map

A list of cooling centers: 2019 Heat Emergency Plan

Hot and humid conditions can cause medical problems such as heat exhaustion and stroke. If you or someone you know needs transportation to a cooling center, call the hyperthermia hotline at 202-399-7093.

DC Water and DC Fire and Emergency Medical Services (FEMS) officials remind the public that unauthorized use of fire hydrants is unlawful, dangerous and damaging. 

Additional Heat Emergency Information Sources