Extreme Temperature Diary- Sunday June 25th, 2023/Main Topic: Introducing The Washington Post Heat Index Tracker

The main purpose of this ongoing blog will be to track planetary extreme, or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉

Main Topic: Introducing The Washington Post Heat Index Tracker

Dear Diary. For most of the U.S. South this will be a very hot week even by late June standards due to what I’ve dubbed historic CAT4 Heatwave British Petroleum. Using my criteria, hundreds of deaths can get blamed on a CAT4 heatwave, which I’m expecting to be blamed from Heatwave B.P. this week, particularly if, God forbid, power should go out in places where the elderly reside. Now we have a new tool to track the heat index for this summer courtesy of the Washington Post.

I invite all to first subscribe to the Washington Post then go take a look at their linked tool daily to keep track of the heat index in association with what I fear will be a devastating heatwave. Here is Sunday’s rendition (For all colorized charts, just hit this link.):

See where Americans are exposed to dangerous heat waves in maps – Washington Post

41 million people in the U.S. may be exposed to dangerous heat today

By Naema Ahmed and John Muyskens

Forecast as of June 25 at 4:00 a.m.

Extreme heat kills more people in the United States than any other weather hazard, and the risk of longer and more frequent heat waves is only expected to increase as climate change worsens.

The Post is tracking the potential for dangerous heat this summer using the heat index, which accounts for the combined impact of temperature and humidity — the higher the humidity, the more difficult it is for the body to cool itself off through sweating. Heat disorders such as heat stroke, heat cramps and heat exhaustion are possible with any extended exposure to a heat index at or above 90 degrees.

Heat illness can set in quickly — in as little as 10 to 15 minutes — when your body overheats and can’t properly cool itself off. This can lead to muscle cramps or spasms, heavy sweating, weakness or tiredness, abnormal pulse rate, dizziness, nausea, vomiting, headache, confusion, fainting, loss of consciousness or death.


80° to 90°F

Fatigue possible with prolonged exposure or physical activity

Extreme caution

90° to 103°F

Heat stroke, heat cramps, or heat exhaustion possible with prolonged exposure or physical activity


103° to 125°F

Heat cramps or heat exhaustion likely, and heat stroke possible with prolonged exposure or physical activity

Extremely dangerous

Over 125°F

Heat stroke highly likely

Source: National Weather Service

Multiple days 0f extreme heat, including warm nights that don’t allow our bodies to cool down, are especially dangerous. A Washington Post analysis of data provided by the nonprofit First Street Foundation estimated that the average number of Americans experiencing at least three consecutive days of temperatures 100 degrees or higher each year will climb from 46 percent today to 63 percent over the next 30 years.

Urban centers, which have fewer trees, less grass, and heat-absorbing pavement, can be up to 20 degrees hotter than nearby neighborhoods, according to the National Oceanic and Atmospheric Administration.

The Weather Service issues heat watches, warnings and advisories when extreme heat — generally a heat index of 100 degrees or higher — is expected or imminent. Any watch, warning or advisory in effect for your location can be seen by entering your location into the lookup box at weather.gov.

Infants and children up to four years old, adults 65 years and older, and people who are overweight, ill, or on certain medications are at the highest risk for heat-related illness, according to the Centers for Disease Control and Prevention. Outdoor workers and athletes are also at greater risk.

The Weather Service recommends wearing light, loosefitting clothing, drinking water often before you get thirsty, reducing or rescheduling strenuous activity, and staying in air-conditioned places during extreme heat.

Dan Stillman contributed to this report.

About this story

Sources: National Digital Forecast Database; Esri.

Additional support from Katlyn Alo, Aaron Brezel, Jake Kara, James O’Toole and Paige Moody. Editing by Monica Ulmanu.

The tracker was originally published June 22, 2023.

By Naema Ahmed Naema Ahmed is a graphics reporter on The Washington Post’s climate and environment team. Before joining The Post, she worked at Axios as a data visualization designer. Twitter

John Muyskens photo

By John Muyskens John Muyskens is a graphics reporter who focuses on climate change and environmental justice. Twitter

Much More:

Here are some “ET’s” recorded from around the planet the last couple of days, their consequences, and some extreme temperature outlooks, as well as any extreme precipitation reports:

Here is more climate and weather news from Sunday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

Today’s News on Sustainable Energy:

More Environmental Stuff:

And from the Weather Department:

More on other science and the beauty of Earth and this universe:

If you like these posts and my work on record temperature ratios, please contribute via the PayPal widget, which has recently been added to this site. Thanks in advance for any support. 

Guy Walton… “The Climate Guy”

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