Most of the US will be blazing hot this weekend as a potentially record-shattering heat wave sets in — with the majority of the country seeing temps above 90 degrees, forecasters predict.

The roasting temps are set to begin on Friday and last through Sunday, and more than 185 million people nationwide were under a heat watch, warning or advisory by Friday morning, CNN reported.

More than 85 percent of the population of the lower 48 states is expected to see temps above 90 degrees throughout the weekend — and in more than half, the mercury will skyrocket above 95 degrees, CNN meteorologist Dave Hennen said.

An excessive heat warning has been declared in the Big Apple — with Mayor Bill de Blasio even declaring a local emergency. He’s ordered tall office buildings across the city to crank their thermostats up to 78 degrees beginning Friday as officials search for ways to slash power consumption.

Temps in the city could soar to 98 degrees both Saturday and Sunday, with the heat indexes at a sizzling 109 degrees, the AccuWeather forecast shows.

“It’s going to be pretty stifling,” AccuWeather senior meteorologist Tom Kines told The Post earlier this week. “And there’s probably going to be one or two nights at least in the city where temps don’t get down below 80.”

Boston, Philadelphia, Baltimore and Washington, DC, are also under excessive heat warnings — and Raleigh, NC, has declared a heat advisory.

In the metro Detroit region, the heat index is expected to top a scorching 110 degrees, local media reported.

Minneapolis, Chicago and Omaha also face heat warnings.

This past June was the hottest on record worldwide, the National Oceanic and Atmospheric Administration said. It’s to be seen whether July will break any records.