More than 132 million people across the central and eastern US are facing blistering temperatures to start the week, with rising humidity making it feel even worse and putting a strain on the energy grid as air conditioners and fans get a workout.

Heat advisories or excessive-heat warnings have been issued from Nebraska to Massachusetts and from North Dakota to Florida, covering all or part of 29 states and more than 38 percent of the US population, according to the National Weather Service. Sweltering conditions will peak Sunday and Monday before gradually easing. The US Southeast will be the last to get some relief, later in the week or next.

READ MORE: Extreme heat waves spark climate emergencies worldwide

The high temperatures, made worse by humidity, have set a smattering of records, particularly in the Southeast. Charlotte, North Carolina, hit a high of 101F (38C) Saturday. Sixty more records may be breached or tied in coming days. In Chicago the combination of temperatures reaching 91F and humidity will make it feel more like 102F Monday. New York City is set to have readings peak Tuesday at 96F in Central Park, but with humidity may feel closer to 105F, the weather service said.

In Washington, DC, the high is forecast to reach 98F Tuesday and 99F Wednesday.  

“It’s miserable but the end is near,” said Brian Hurley, a senior branch forecaster at the US Weather Prediction Center. “A couple of days to go, maybe more than a couple of days if you are in the Southeast.”

READ MORE: Brutal summer heat wave has Europe sweating on its future

Heat threatens human life, as well as stressing electric grids and transportation networks. From 1979 to 2022 more than 14,000 Americans died from heat-related causes, according to the US Environmental Protection Agency.

Utilities are gearing up for continued high demand. PJM Interconnection LLC, a grid operator that moves electricity across 13 states and the District of Columbia, issued hot weather alerts for its Mid-Atlantic and Southern regions Sunday and for its entire operating area on Monday. It also called on power plants to be ready for service and that it may curtail exports to neighboring grids if demand rises.

A wide area of the US faces a moderate heat risk Sunday, with as many as 88.4 million people under a major threat and 10.8 million enduring extreme conditions, mainly along the eastern seaboard from Washington to Florida, the weather service said.

READ MORE: US cities face record high temperatures on worst day of heat wave

The heat will start to ease as a weather front pushes south, leaving lower temperatures and milder humidity in its wake, Hurley said. In a week, a large part of the central and eastern US will likely be cooler than normal for early August, according to the US Climate Prediction Center.

In addition to the heat, ground-level ozone parts of New York and New Jersey may make breathing difficult for the young, the elderly and people with respiratory or heart conditions, the weather service said. Further north, across Upstate New York and New England, smoke from Canadian forest fires is also harming air quality. Much of that threat should start to diminish in the coming days, Hurley said.