A heat wave is expected to bake the U.S. this week. Here's a look at the latest weather forecast — and how to stay safe.

The extreme heat is set to come the same week as the summer solstice.

A man walks past a sign in Joshua Tree, Calif., displaying the temperature as 104 degrees Fahrenheit.
Joshua Tree, Calif., experienced triple-digit temperatures last week. And now a heat wave is set to hit large swaths of the U.S. (Gina Ferazzi/Los Angeles Times via Getty Images)

Millions of people across the U.S. are facing an extreme heat wave this week, with temperatures hitting well over 100 degrees in some areas.

In the Midwest and North East, cities St. Louis, Chicago, Philadelphia and upstate New York will experience a high of 105 degrees, according to the Weather Prediction Center. The heat wave is more brutal in the South, where cities like Rio Grande Village, Texas became the hottest place in the U.S. on Monday at 114 degrees, per NBC News.

It's not over yet. The heat wave will continue early in the week as it passes through states like Illinois, Ohio and Pennsylvania before traveling northeast towards Maine by Thursday.

It’s rare to have such high temperatures so early in the year. This follows 2023’s record-breaking heat waves, which experts say were a result of climate change.

🌡️ Where is extreme heat happening?

There was already a heat wave in the Southwest this week. Temperatures hit 113 degrees in Phoenix, Ariz., which sent people scrambling for relief. However, extreme heat is hardly over in the United States, and now the heat wave is also heading to the Midwest and Northeast.

Temperatures are expected to hit the mid- to high 90s in many areas, according to the Associated Press. The Ohio Valley and the Northeast (the latter of which just saw a bout of thunderstorms) will continue to see daily records of extreme heat, while Detroit may see its worst heat wave in two decades — it hit 96 degrees on Monday before tapering down to 90 degrees on Tuesday, according to weather reports.

Cities like Philadelphia and Boston will see record highs — weather forecasts have temperatures reaching 97 degrees and 95 degrees through next Sunday, June 23.

🥵 Meteorologists say a 'heat dome' is to blame

Across the U.S. in general, record-breaking highs are likely, with temperatures soaring 15 to 25 degrees above average, especially from Tuesday through Friday. This means many areas will experience days in the 90s. That's significantly hotter than usual and will affect millions who aren't accustomed to such prolonged heat.

The scorching temperatures are due to a "heat dome" — a weather phenomenon that occurs when a large area of high pressure in the atmosphere traps hot air underneath it, leading to hot weather for an extended period of time.

Tiger Woods wipes his face in front of a sign warning of extreme temperatures during the U.S. Open golf tournament on Friday in Pinehurst, N.C.
Tiger Woods wipes his face in front of a sign warning of extreme temperatures at the U.S. Open golf tournament Friday in Pinehurst, N.C. (Frank Franklin II/AP)

The National Weather Service has a heat map of the United States to indicate temperature patterns. As of Saturday, it places nearly all of the country (with the exception of parts of the Northwest and Northeast) in at least the “minor” level of concern, defined as a level of heat that “affects primarily those individuals extremely sensitive to heat, especially when outdoors without effective cooling and/or adequate hydration.”

However, this changes over the course of the week as heat patterns shift — with more of the country expected to experience “major” and “extreme” heat-related impacts.

On Sunday, much of the Midwest will be affected by heat, with temperatures creeping into the extreme category by Monday. On Tuesday, the Chicago area and Michigan will be primarily affected by extreme heat, with those temperatures shifting toward the Northeast come Wednesday and Thursday.

☀️ Is this the start of a very hot summer?

The Weather Company and Atmospheric G2 believe that the summer of 2024 may be one of the hottest on record in the United States. Above-average temperatures will likely continue throughout July from New England to the Great Lakes, as well as in the central and northern Plains and Rockies, with Colorado and the High Plains seeing the highest temperature increases when compared to what they typically see during the month.

In August, the northern Plains and upper Midwest are expected to experience temperatures well above average. Additionally, areas stretching from the Southwest to the Great Lakes, upstate New York and northern New England are also forecast to have a warmer-than-usual August.

🧊 How to stay safe in extreme heat

It’s important to know that extreme heat can be deadly: in 2023, more than 2,300 people died of conditions related to high temperatures, and some predictions indicate that 2024 could see more deaths related to heat.

If you are experiencing extreme heat this year, make sure to follow guidelines to keep you and your family safe and healthy. Keep these tips in mind: