The Planet's Hottest Day on Record Happened Twice This Week

July 4, 2023 was Earth’s hottest day since record keeping began, data from the U.S. Centers for Environmental Prediction shows, with the average temperature reaching 62.92 degrees Fahrenheit. This broke a record set just one day earlier, on July 3, when temperatures topped out at 62.62 degrees Fahrenheit. The previous record for the hottest day topped out at 62.45 degrees, tied between August 14, 2016 and July 24, 2022.

The modeling system which scientists currently use to estimate average temperatures dates back to 1979 and utilizes data from ships, buoys, satellites and weather stations to determine results. While temperature tracking dates back to around 1880, scientists utilize evidence captured through ice cores and tree rings to determine temperatures predating the 19th century.

“These data tell us that it hasn’t been this warm since at least 125,000 years ago, which was the previous interglacial,” Paulo Ceppi, a climate scientist at the Grantham Institute in London, told The Washington Post.

Part of the reason for the rapid record-setting has to do with the presence of El Niño, which causes much dryer and warmer conditions than are typical in Canada and North America whilst simultaneously causing an influx of moisture in the southeast U.S. and across the Gulf Coast. Specific heat waves need to be studied to definitively link them to climate change, but experts are clear that climate change is causing warming temperatures and more extreme weather.

Friederike Otto, a senior lecturer in climate science at the UK’s Grantham Institute for Climate Change and the Environment at London’s Imperial College, told CNN in no uncertain terms that the holiday temperature is “not a record to celebrate and it won’t be a record for long, with northern hemisphere summer still mostly ahead and El Niño developing.” Otto additionally remarked to Reuters that this latest “milestone” is “a death sentence for people and ecosystems.”

A break in the heat wave does not seem likely any time soon. On Tuesday, physicist Dr. Robert Rohde posted to Twitter an announcement of Monday’s record-beating temp. “NCEP has placed Earth's average temperature yesterday as the hottest single day thus far measured by humans,” Rohde wrote to accompany a graph charting world temperatures since 1979.

“We may well see a few even warmer days over the next six weeks,” Rohde ended his post.

2023 has already been a year of devastating heat waves. While China set an all-time record for the highest number of hot days over a period of six months since record keeping began, heat waves in India claimed at least 44 lives so far. Last month, Texas and southern states were hit with a debilitating heat wave, with heat indexes predicted to be as high as 120 degrees Fahrenheit.