Heat Dome Brought Record-Breaking Temperatures

A massive heat dome spread triple-digit temperatures and smashed record highs across a vast stretch of the nation's mid-section and prolonged the persistent searing heat in the South.

July was the record hottest month for dozens of cities in the southern U.S., as well as for the planet.​ This heat wave is not only keeping the South sizzling, but also spread its tentacles into the nation's mid-section, including areas that have not been nearly as persistently hot so far this summer.

A​ record strong heat dome, for some. The instigator for this expanding heat wave was something colloquially dubbed a "heat dome".

T​hat's a bubble of high pressure and warm air that suppresses clouds and rain and diverts the storm track well to the north. When those happen in the heart of summer, they can lead to extended heat waves near their core.

I​t turns out this particular heat dome is one of the strongest we've seen in some parts of the Plains.

Without getting too deep in the weeds, a parameter meteorologists examine to ascertain the strength of such heat domes - and troughs of low pressure aloft - already topped all-time records in parts of Kansas, Missouri and Nebraska.

That isn't the only major record we saw.

All time record highs or hot lows were already tied or set in these locations:

-​Alexandria, Louisiana (110 degrees Aug. 19; previous record was 109 on Sept. 1, 2000)

-​College Station, Texas (112 degrees Aug. 20; tied previous record from Sept. 4, 2000)

-​Gulfport, Mississippi (107 degrees; previous record 104 degrees last set Aug. 30, 1951)

-H​ouston tied its all-time hottest day on record Aug. 24 with a high of 109 degrees at Bush Airport (previously set on Sept. 4, 2000 and Aug. 27, 2011).

-​Lufkin, Texas (110 degrees Aug. 20; tied previous record from Sept. 4, 2000 and Aug. 19, 1909)

-​New Iberia, Louisiana (105 degrees Aug. 23; previous record was 104 set on July 31, 2023)

-​New Orleans, Louisiana (104 degrees Aug. 27; previous record set on Aug. 22, 1980)

-​Shreveport, Louisiana (110 degrees Aug. 25; tied previous record set on Aug. 18, 1909)

-​Sioux Falls, South Dakota (81 degree low Aug. 22 tied their hottest daily low set in 1936 and 1938)

B​aton Rouge, Louisiana, didn't set an all time record Aug. 24, but its high of 106 degrees was its hottest temperature in 114 years.

M​anhattan, Kansas, soared to an incredible 115 degrees on Aug. 19, just 1 degree shy of their all time Dust Bowl record. It was also the nation's hottest location that day, a rarity in summer anywhere other than Texas or the Desert Southwest, according to weather historian Christopher Burt.

S​ome heat index values were simply off the charts, as well.

C​hicago experienced a heat index of 120 degrees on Aug. 24, breaking its highest heat index on record. It also reached 100 degrees for the first time since July 6, 2012.

Peoria, Illinoisreached a 122-degree heat index Aug. 23, higher than their previous record from the historic July 1995 heat wave.

M​iami, Oklahoma, reached a heat index of 126.7 degrees on Aug. 21, setting an all-time heat index record for the state.

S​ioux City, Iowa, set a new record for their hottest heat index on Aug. 21 of 122 degrees.

F​alls City, Nebraska, recorded a heat index of 128 degrees on Aug. 19, their highest in 42 years of records, according to the National Weather Service.

L​awrence, Kansas, recorded a heat index of 134 degrees on Aug. 20 - thanks not only to triple-digit heat, but also a dew point of 84 degrees.

These are just a few of the notable heat index records set during this heat wave and during the summer, as NOAA's Weather Prediction noted.

Here's how to stay safe: The hot conditions will be particularly dangerous for vulnerable groups, such as the sick and the elderly. The NWS has useful heat safety tips that can be incorporated into a daily routine when extreme heat sets in.

-Job sites: Stay hydrated and take breaks inside as often as possible. Remember that in temperatures above 110 degrees, you will not know that you are sweating.

-Indoors: Check up on the elderly, sick and those without air conditioning.

-In vehicles: Never leave children or pets unattended – look before you lock.

-Outdoors: Limit strenuous activities and find shade. Drink plenty of water and avoid alcohol.

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Jonathan Erdman is a senior meteorologist at weather.com and has been covering national and international weather since 1996. His lifelong love of meteorology began with a close encounter from a tornado as a child in Wisconsin. He studied physics at the University of Wisconsin-Madison, then completed his Master's degree working with dual-polarization radar and lightning data at Colorado State University. Extreme and bizarre weather are his favorite topics. Reach out to him on X/Twitter, Facebook and Threads.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.