SOUTHERN MARYLAND — Dangerous heat and humidity are expected to grip Southern Maryland through the end of the week, with a Heat Advisory in effect Wednesday and an Extreme Heat Watch posted for Thursday and Friday.
The National Weather Service Baltimore/Washington office issued the updated alert at 10:27 a.m. Wednesday, July 1, 2026. The Heat Advisory remains in effect until 8 p.m. Wednesday, with heat index values up to 108 expected.
An Extreme Heat Watch is also in effect from Thursday morning through Friday evening, when dangerously hot conditions could push heat index values as high as 112.
The alert covers portions of Washington, D.C., central, north-central, northeast, northern and southern Maryland, as well as parts of central, northern and northwest Virginia.
Southern Maryland is expected to see some of the hottest conditions of the week heading into the July 4 weekend. Forecasts show highs near 97 in Leonardtown on Wednesday, 99 on Thursday and 102 on Friday. La Plata is forecast to reach 99 Wednesday, 101 Thursday and 105 Friday.
Forecasters warned that heat-related illnesses increase significantly during extreme heat and high humidity events. Hot temperatures and high humidity can cause heat illnesses, especially for people without reliable access to air conditioning.
The National Weather Service also noted that dangerous heat may linger into Saturday. Prolonged extreme heat could impact power, water and transportation systems.
Residents are urged to limit time outdoors, drink water frequently, stay in air-conditioned spaces when possible and avoid strenuous activity during the hottest part of the afternoon. People working outside should take frequent breaks in shade or air conditioning.
Officials also urge residents to check on older adults, neighbors, children and anyone without reliable access to air conditioning. Children and pets should never be left inside vehicles, even briefly.
Anyone experiencing signs of heat illness, including confusion, fainting, chest pain, difficulty breathing or loss of consciousness, should call 911.
Residents can check the latest Southern Maryland forecast anytime at TheBayNet.com/weather.
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