An “Excessive Heat Warning” is up for all of South Florida today, with forecasters saying that the “feels like” temperature could hit 115 degrees Fahrenheit or even hotter on Key Biscayne.
By 10 a.m, the heat index had already reached 109 degrees at the University of Miami’s weather station on Virginia Key.
“This is the first time that an Excessive Heat Warning has ever been issued for Palm Beach, Hendry, and Glades counties,” the National Weather Service said on X, formerly known as Twitter. The warning is in effect until 7 p.m. today.
It could be even more sweltering in Key Biscayne, said meteorologist Cameron Pine at the National Weather Service office in Miami. He said that’s because water temperatures are five degrees over normal, leading to higher local humidity. That would make the island feel hotter than downtown Miami or Miami International Airport, he said.
South Florida had already been under a Heat Advisory, but Pine said a combination of high pressure, high humidity, record ocean temperatures, and delayed rainfall are setting the stage for the warning.
“In terms of what we can issue, we are at the highest level,” Pine said in a year that has shattered records all over Florida. The advisory urges people to stay cool and hydrated.
“The heat index in Miami was at or above 105°F for eight hours on Monday, the most ever observed in the city’s history,” said Rosenstiel meteorologist Brian McNoldy. “The heat index has now been 105°+ for 103 hours this year so far, more than double the previous year.
If there is a silver lining, it’s that today — August 8th — is climatologically the date of the peak heat index. “We made it to the hump, “ he said in a social media post.
One factor driving the heat wave is that afternoon thunderstorms –which typically form and reduce the heat– are being delayed by dry upper level air, Pine said.
Pine said the forecast says the heat index should drop — just a bit — this weekend.
This story has been updated.
Tony Winton is the editor-in-chief of the Key Biscayne Independent and president of Miami Fourth Estate, Inc. He worked previously at The Associated Press for three decades winning multiple Edward R. Murrow awards. He was president of the News Media Guild, a journalism union, for 10 years. Born in Chicago, he is a graduate of Columbia University. His interests are photography and technology, sailing, cooking, and science fiction.