The Baltimore health commissioner is urging residents to prepare for 100-degree heat on Monday that could pose dangers for the young and elderly.
The temperature is forecast to reach as high as 100 degrees, but it could feel as hot as 109 with humidity and wind factored in, according to the National Weather Service.
"Heat is a silent killer and a public health threat, particularly for the young, the elderly and those in our city who are the most vulnerable," Dr. Leana Wen said Sunday in a Code Red advisory. "With ... extreme heat expected, it is important for all residents to protect against hyperthermia and dehydration."
Temperatures reached 95 degrees Sunday afternoon at the Inner Harbor and 94 degrees at Baltimore-Washington International Thurgood Marshall Airport, the National Weather Service said. The record high for July 24 was set in 2010 with 101 degrees recorded at the airport.
Maryland is experiencing a heat wave that could be the Mid-Atlantic's longest since 2012.
The heat is not unusual for July, said Kevin Witt, a meteorologist with the Baltimore-Washington office of the National Weather Service.
"July is typically the warmest time of year," he said. "It's not out of the question to get these type of temperatures; you just need the right conditions."
Witt said temperatures could stay above 90 degrees for the rest of July.
"People should avoid strenuous activities outside between the hours of 12 and 4," he said.
Rain and thunderstorms were expected early Monday and possibly late afternoon but would do little to cool down the region, the National Weather Service said.
The nonprofit Clean Air Partners suggested setting air conditioners to 78 degrees to save energy.
Officials have recorded three heat-related deaths in Maryland this summer. There were six heat-related deaths last year. In 2012, there were 46.
Baltimore schools have canceled all summer programs for Monday. Free breakfast and lunch still will be served to children from 8:30 a.m. to noon at 18 locations.
City health officials said people should stay indoors as much as possible and drink lots of water. They should avoid alcohol and caffeine, which can cause dehydration.
Wen asked residents to check in with older and sick neighbors, who are the most likely to suffer heatstroke.
Symptoms for heatstroke include confusion, skin that is hot and flushed or cool and clammy, lightheadedness and sometimes nausea.
The city warned against leaving pets or children inside cars for even short periods of time.
"We can prevent heat from killing our citizens," Wen said. "It's important to stay cool, stay hydrated and stay in touch with your neighbors."
Cooling centers will be open from 8:30 a.m. to 4:30 p.m. Locations are listed on the city health department's website at health.baltimorecity.gov.