The summer may be coming to a close for many families preparing to send their children back to school, but summer temperatures aren't going away any time soon.
A sweltering heat wave and increased humidity threatened to bring scorching temperatures across the Northeast, stretching from parts of Virginia up through New England with pockets farther out west in Missouri and Michigan, on Tuesday and Wednesday.
Approximately 68 million people were under heat advisories on Tuesday and Wednesday, according to NBC News' Al Roker.
In parts of Massachusetts, Connecticut and Rhode Island the maximum heat index was forecast in the triple digits on Tuesday and Wednesday, according to the National Weather Service, and the overwhelming majority of the area was under a heat advisory.
Excessive heat watches were issued for parts of the Connecticut River Valley and eastern Massachusetts for Tuesday and Wednesday, where heat index values had the potential to reach 105 degrees.
Summer weather across the US in 2018
Summer weather across the US in 2018
NEWPORT BEACH, CA - AUGUST 17: A man and his nephew enjoy the warm water at Salt Creek Beach in Dana Point on Friday, August 17, 2018. (Photo by Paul Bersebach/Orange County Register via Getty Images)
NEW YORK, NY - AUGUST 17: People cool themselves during a warm day at Central Park on August 17, 2018 in New York City. Severe thunderstorms and even an isolated tornado could strike New York City on Friday. (Photo by Eduardo Munoz Alvarez/Getty Images)
WEEHAWKEN, NJ - AUGUST 17: A man takes a look of the haze over the New York skyline and One World Trade Center on August 17, 2018 in Weehawken, New Jersey. Severe thunderstorms and even an isolated tornado could strike New York City on Friday. (Photo by Eduardo Munoz Alvarez/Getty Images
NEWPORT BEACH, CA - AUGUST 10: A surfer loses it on a wave in Newport Beach on Friday, August 10, 2018. A swell from Hurricane John will bring larger waves to south-facing beaches through the weekend. (Photo by Paul Bersebach/Orange County Register via Getty Images)
A man sunbathes on Venice Beach in Los Angeles, California on August 7, 2018. Temperatures climbed to near 100 degrees as a week-long heat wave continues in Southern California. (Photo by Ronen Tivony/NurPhoto via Getty Images)
WELLFLEET, MA - JUNE 21: Mark Wilke and his wife Sharon enjoy the first day of summer at White Crest Beach in Wellfleet, MA on June 21, 2018. (Photo by Craig F. Walker/The Boston Globe via Getty Images)
ARLINGTON, VA - JUNE 20: A pedestrian passes near the Netherlands Carillon as the Washington Monument and United States Capitol are seen at sunrise on Wednesday June 20, 2018 in Arlington, VA. The summer solstice is Thursday. (Photo by Matt McClain/The Washington Post via Getty Images)
Pedestrians watch sailboats and windsurfers on the Charles River on the summer solstice in Boston, Massachusetts, U.S., June 21, 2018. REUTERS/Brian Snyder
A women keeps in the shade of her umbrella as she tries to beat the heat at Cardiff State beach in Encinitas, California, U.S. July 6, 2018. REUTERS/Mike Blake
A man cools off in fountain on the Rose Kennedy Greenway during a summer heat wave in Boston, Massachusetts, U.S., July 2, 2018. REUTERS/Brian Snyder
OLD ORCHARD BEACH, ME - JULY 4: Ryan Parsons, left, of Unity watches as his daughter, Lily, 10, rides the waves on her inflatable whale at Old Orchard Beach on a hot, beautiful Fourth of July. The Parson family was spending the day at the beach keeping cool and watching the fireworks. (Staff photo by Jill Brady/Portland Press Herald via Getty Images)
NEW JERSEY, USA - JUNE 30: People enjoy Manhattan skyline at the Hamilton Park during the hot weather in New Jersey, United States on June 30, 2018. (Photo by Atilgan Ozdil/Anadolu Agency/Getty Images)
NEW YORK, July 2, 2018 -- People cool themselves at a fountain at Washington Square Park in New York City, the United States, on July 2, 2018. The highest temperature reached 35 degrees Celsius in New York City on Monday as a result of a prolonged heat wave. (Xinhua/Wang Ying via Getty Images)
NEW YORK, USA - JULY 23: Rain clouds are seen over Lower Manhattan in New York, United States on July 23, 2018. (Photo by Atilgan Ozdil/Anadolu Agency/Getty Images)
NEW JERSEY, USA - JULY 27: People walk with their umbrellas during a rainy day at the Liberty State Park in New Jersey, United States on July 27, 2018. (Photo by Atlgan Ozdil/Anadolu Agency/Getty Images)
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In Connecticut's Milford and West Haven school districts, schools will close early on Tuesday and Norwalk school district will dismiss early on Wednesday, according to NBC Connecticut.
Similarly, in Philadelphia, the heat was expected to be so intense, the school district said students would be dismissed early at 1 p.m. ET on both Tuesday and Wednesday. The district also canceled all after school activities.
In parts of New York, the heat index for the two-day stretch topped out at 102 degrees, according to the NWS.
New York Gov. Andrew Cuomo issued a statement, urging New Yorkers to use pools, beaches and cooling stations to beat the heat during the week.
"Be sure to check on neighbors who may be at risk and limit strenuous activity to ensure that you and your family remain safe and healthy during this stretch of extreme heat," Cuomo said.
Farther south in parts of Virginia and in Washington, D.C., heat advisories were in effect from 12 p.m. ET to 8 p.m. ET, according to the NWS.
Out west, parts of Missouri and Michigan were both facing their own heat advisories with a heat index that could reach as high as 105 degrees for St. Louis and hot and humid conditions forecast in the Detroit area, according to the NWS.
Those looking to escape the heat are expected to find relief on Thursday as temperatures begin to fall across the region, Roker said.