Miami hit 100 degrees fahrenheit on Tuesday for only the second time in more than 130 years of records, tying its all-time high as a heat wave stretched from Texas to the Southeast.The city’s only previous 100-degree reading was recorded on July 21, 1942. The latest record also fits into a broader trend of extreme warming linked to human-caused greenhouse gas emissions.Yet Miami’s 100-degree record looks modest beside temperature extremes elsewhere in the US. Kingfisher, Oklahoma, reached 112 degrees on Tuesday, a record for August 18, while Oklahoma’s all-time state high stands at 120 degrees and Minnesota’s at 115. Florida’s statewide record is 109 degrees, according to Cable News Network (CNN).Miami’s relatively low record is largely a product of its coastal setting. The nearby ocean heats more slowly than land, while regular Atlantic sea breezes typically bring cooler marine air inland and help keep daytime temperatures from reaching the extremes more common in the country’s dry interior.This moderating effect weakened on Tuesday, when west winds kept Miami’s usual cooling sea breeze from developing along the coast. Drier regions can heat much more sharply, helping explain why the highest temperatures in the US are generally recorded in the desert Southwest rather than the humid Southeast.Miami’s high humidity, however, means temperatures do not need to reach desert-like levels to become dangerous. Heat and moisture together can make it harder for the human body to cool itself, increasing the risk of heat-related illness.The city and much of the Southeast have also seen a sharp rise in extreme heat in recent decades. Miami now records 44 more above-normal summer days than it did in the 1970s, according to Climate Central, a US-based climate research group.Miami’s average temperature during June, July and August has risen by 2.6 degrees fahrenheit. Climate Central also found that the annual number of days classified as dangerous humid heat — when the maximum wet-bulb temperature reaches at least 77°F — rose from an average of 50 in the 1970s to 117 during 2016-2025.The group estimated that human-caused climate change, largely driven by the burning of fossil fuels, accounted for about 80 of those 117 days.Miami’s heat index, which accounts for the effect of humidity on how hot conditions feel, reached 107 degrees on Tuesday. A stalled heat dome, a persistent area of high pressure that traps hot air, drove the wider heat wave, which continued across much of the southern US on Wednesday.Heat advisories covered all of the Florida Peninsula on Wednesday except the Florida Keys, with Miami forecast to reach the mid-to-upper 90s as dangerous heat and humidity persisted.
