The Fourth of July is known for sweaty backyard barbecues, scorching Major League Baseball day games, and, if you’re lucky, cooler nighttime temperatures as fireworks finally pop after sunset.

But two heat waves on each side of the United States will make this holiday weekend an even more memorable scorcher for tens of millions of Americans, with less relief than usual at night.

The western region is in the middle of a long-term heat wave that could last well through the holiday weekend, while the Southern Plains to the Southeast Gulf Coast will swelter in humid heat.

Rain is more likely across the middle of the country, from the Northern Plains through the Midwest and into the Mid-Atlantic.

Across the Northeast, slightly abnormal heat will build on Thursday and last through the weekend. This is not expected to be the same level of heat experienced during the June heat wave, but it will still be a sticky heat.

As contestants choke down hot dogs at Nathan’s Famous Hot Dog Eating Contest on Long Island on Thursday — absent longtime champion Joey Chestnut — there is only a slight, 30 percent chance of rain. This percentage will increase in the Northeast as the weekend progresses.

The South won’t be as lucky and will continue to see high, humid heat, which is more typical of the end of July than the beginning. As thousands of runners lace up their shoes to begin Atlanta’s 55th running of The AJC Peachtree Road Race at 7 a.m. on Thursday, it will feel like 77 degrees at the starting line. As the last runners cross the finish line later that morning, it will feel like the mid-90s. By the afternoon, as in other locations across the South, temperatures combined with humidity will make it feel more like the upper 90s, if not the 100s. That’s a trend that will continue through the long weekend.

There is some relief to be found. While much of the country will have temperatures above average for this time of the year, areas from the Northern Rockies into the Northern and Central Plains will see cooler-than-average temperatures.

Places like Chicago may have morning rain on Thursday. Although there is a slight chance of an afternoon thunderstorm, it will likely be dry. The upper Midwest, especially Minnesota and Northern Iowa, is most at risk for rainfall on Thursday. This is the one spot that doesn’t need anymore, as rivers are still under flood warnings after persistent rains this past month.

Out West, the long heat wave will push desert temperatures well past 100. The persistent heat will cause hazardous conditions not only on Thursday but also through the weekend and into next week. The only relief may come from joining others on another 4th of July pass time and hanging at the beach; even then, it might not be as much relief as typical.