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.
“Even if it had been two or three months from now, like July or August, it still would have been pretty astounding to have two consecutive days with 112-degree heat index here,” McNoldy said. “For any time of the year, that would be extraordinary. But for mid-May, it was completely unprecedented. Not even close.”
Last summer was the hottest on record for Miami — and the entire planet. Forecasters say above average temperatures are likely for much of the country over the next three months, and the National Oceanic and Atmospheric Administration said last week that 2024 is already on pace to rank among the five warmest years in recorded history.
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.
“It’s certainly warmer now than 2023 was to this point,” McNoldy said. “I don’t know what the rest of 2024 has in store for us, but I hope this is not foreshadowing of breaking the 2023 records.”
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.
“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 every year in the United States than any other weather disaster, according to the weather service.
