Miami hit an all-time high of 100 degrees Fahrenheit on Tuesday, amid a widespread heatwave affecting areas from Texas to the Southeast. The heat wave caused by the stalled heat dome continued on Wednesday.
Yes, it’s important that Miami tied the all-time record. This is another example of extreme warming trends caused by climate pollution. But perhaps more surprising is that this record is relatively cool in Miami, a city famous for its heat.
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As Miami reached 100 degrees on Tuesday, high temperatures rose well above that in parts of Oklahoma, reaching a daily high of 112 degrees in Kingfisher. The highest temperature on record in Florida is 109 degrees. It’s 120 degrees in Oklahoma. It’s 115 degrees in Minnesota.
So what happened to Florida?
Miami’s relatively low all-time record has to do with its proximity to the ocean and the city’s typically high levels of humidity. Heating very humid air to extreme levels by the sun’s energy is more difficult than increasing the temperature of dry air. Much of the sun’s energy is spent evaporating moisture in the air, so in dry climates more of the sun’s energy can be spent directly heating the air.
This is one reason why the hottest places in the United States are in the desert Southwest, rather than the humid Southeast.
Still, Miami and the rest of the Southeast have seen a sharp increase in heat waves in recent years, including a dangerous combination of heat and humidity that can cause people to die from heatstroke.
According to Climate Central, a nonprofit climate research and communications organization, Miami now has 44 more days of above-average temperatures during the summer compared to summers in the 1970s.
According to a study by Climate Central, temperatures in the city rose an average of 2.6 degrees Celsius during the summer months of June, July and August. The city has seen a significant increase in the number of dangerously humid and hot days per year, from 50 in the 1970s to 117 from 2016 to 2025, according to Climate Central researchers.
They attributed a significant portion of today’s dangerously hot days (80 days) to anthropogenic climate change caused by burning fossil fuels. Tuesday was a good example of a day with dangerous levels of heat and humidity, with the heat index, which measures how the air feels on the human body, rising to 107 degrees.
Miami is expected to be unusually hot again on Wednesday, with a heat advisory in effect for the entire Florida peninsula except the Florida Keys, and high temperatures in the city expected to be in the mid to upper 90s.
