It’s Abnormally Hot in Texas and Florida Right Now

Scorching heat and humidity have descended over parts of Texas, the Gulf Coast and South Florida this week — a bout of early-season extreme heat that has experts bracing for what’s to come.
A full month before the official start of summer, Miami is already in the midst of its hottest May on record, according to experts.
The city’s heat index — a measure of what conditions feel like when humidity and air temperatures are combined — hit 112 degrees Fahrenheit over the weekend, smashing the previous daily record by 11 degrees, according to Brian McNoldy, a senior research associate at the University of Miami. The weekend heat index also beat Miami’s monthly record by 5 degrees, he wrote in a post on X.
Last summer was the hottest on record for Miami — and the entire planet. Forecasters say the coming season could match or surpass the temperatures seen in 2023.
Miami’s recent 112-degree heat index reading was recorded both Saturday and Sunday, marking only the second time in the city’s recorded history that there have been back-to-back days of heat index values at or above that level, according to McNoldy. The other instance was Aug. 8 and 9, 2023.
“But it’s only mid-May!” he wrote. “To anyone who was hoping 2023 was a freak anomaly: nope.”
Miami has already expanded the time period it considers to be the official heat season to span from May 1 to Oct. 31 annually — a response to earlier onsets of high heat and humidity.
Meanwhile, a heat advisory is in effect across much of south Texas. Temperatures up to 113 degrees can be expected in some places, particularly along the Rio Grande, according to the National Weather Service.
The agency said heat index values between 110 degrees and 120 degrees are expected this week, with still more dangerous heat lingering into the weekend.
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“As a result, major to extreme risks of heat-related impacts are expected across South Texas,” the weather service said in its advisory. “Be sure to stay cool, drink plenty of water, and take frequent breaks if you are spending time outside!”
High heat and humidity, including heat indexes around 100 degrees, are also expected in Houston in the coming days. The city is still reeling from last week’s deadly storms, with tens of thousands of residents still without power.
Studies have shown that climate change is making early-season heat more likely, in addition to fueling more frequent, intense and longer-lasting heat waves.
The consequences can be deadly. Heat kills more people each year in the United States than any other weather disaster, according to the weather service.
It’s already the hottest May in Miami, ever — at least judging by the heat index, a “feels like” measure that combines temperature and humidity.
Last weekend’s record temps jacked up the average heat index into a record for May, according to Brian McNoldy, a senior research associate at the University of Miami’s Rosenstiel School of Marine, Atmospheric and Earth Science.
“The type of heat and humidity we had this weekend would’ve been exceptional even in another three months,” said McNoldy. “These temperatures in May are completely off the charts.”
McNoldy created an online chart that updates daily with the cumulative amount of time the heat index spent above various heat index thresholds. The reading in 2024 already rivals or tops nearly all end-of-summer 108°+ and 110°+ marks. (It’s Abnormally Hot in Texas)
Usually, the hottest time of the year is the first and second weeks of August but this weekend temperatures peaked at 112 degrees heat index— that’s a stunning six degrees hotter than any previous May heat index recorded.
Early-season heat events have some of the highest rates of heat illness and heat-related deaths because people are not prepared for it. Nearly 1,200 people die from heat every year, according to NOAA, and record-breaking heat waves fueled by climate change add to that threat.
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Climate change makes things like these record highs more likely. But over the weekend McNoldy said there was also the “perfect combination” of a high pressure ridge (where air sinks and warms), fewer clouds and moist air coming in from the southwest.
Other records were broken over the weekend too. Sunday’s nighttime temperatures averaged (the average of the high and low temperature) to 89 degrees. That is a tie for the third-highest daily nighttime average temperature ever recorded in Miami, and that’s never happened as soon as May.
As of Monday, there had also been four new high daily average temperature records and record-high humidity levels in the past five days.
The National Weather Service is predicting that the record-breaking heat will ease in the coming week, thanks in part to the increasing relief of rain. But it also signals the potential for another scorching summer ahead. Summer 2023 was the hottest on record in Miami.
“What this looks like for June, July, August? Who knows,” McNoldy said. “But it’s not off to a promising start.”