What is the heat index near you today? See map of real-feel temperatures across the US
Summer may not have officially arrived, but the heat has.
A heat wave will settle and persist across the Great Lakes, Ohio Valley and the Northeast through the next few days, according to the National Weather Service.
In New England, temperatures are expected to reach the mid- to upper 90s Tuesday and Wednesday, and could hit the century mark Wednesday and Thursday afternoon. The NWS says "numerous record-tying/breaking high temperatures are possible."
From eastern Iowa to the Atlantic Coast of Maryland and up to northern Maine, heat advisories were set to take effect at noon and remain active until Thursday night, according to the National Weather Service.
The agency warns that the early arrival of the heat, the duration, abundant sunshine and lack of relief overnight will "increase the danger of the heat wave beyond what the exact temperature values would suggest," especially for those with inadequate air conditioning.
As of Tuesday morning, over 64 million people in the U.S. were under heat advisories, with a majority of them being in the Northeast and Midwest.
Tuesday weather outlook:Extreme heat and, yes, some snow and below-freezing temperatures
US temperature, heat index map
All of western New York could experience heat index values, or "feels like" temperatures, as high as 104 degrees Tuesday. In parts of Indiana and Michigan, the apparent temperature could fall between 95 to 100 degrees through the week. In Washington, D.C., meteorologists anticipate heat index values up to 101.
The weather service forecasts heat indexes in the triple digits across a swath of New England on Wednesday and Thursday afternoon. While hot weather is not uncommon this time of year, the magnitude of the heat wave and its early arrival is notable.
Heat safety tips
The Centers for Disease Control and Prevention, the National Weather Service and other agencies recommend that people avoid being outside during the hottest time of the day when there's active heat advisories in effect. For those who don't have that option, experts suggest working in the shade as well as taking frequent breaks and drinking plenty of water.
During periods of extreme heat, temperatures inside unpowered vehicles can reach deadly temperatures in minutes. People should never leave children or pets inside cars unattended, especially during a heat wave, the weather service says.
People at greatest risk are young children, elderly people, outdoor workers and those who have chronic diseases, mental illness or take certain medications that make it difficult to regulate their body temperatures, the CDC said. Additionally, those who may not have access to reliable AC are at risk, as are others who live in areas called urban heat islands that are warmer due to more pavement and buildings – and less green space.
Experts previously told USA TODAY it's best to check in on those who may be vulnerable with heat.
Beat the heat:Here's what a heat wave really is, plus how to keep yourself safe
National weather watches and warnings
Contributing: Christopher Cann, USA TODAY
Gabe Hauari is a national trending news reporter at USA TODAY. You can follow him on X @GabeHauari or email him at [email protected].