On Sunday July 27, 2025, Tampa, Florida reached the 100 degree F mark for the first time in recorded history. I am sure this comes as a surprise to many readers who have spent any time in central Florida. Certainly, some of you are saying, “How can this be? It is hot in Florida in July.” Let’s dig a bit deeper into this stunning piece of weather and climate history.

At 3:30 pm Sunday, the National Weather Service in Tampa Bay wrote, “Tampa broke the all-time high temperature record today 100 degrees F!…. The old record was 99 degrees F last set on June 26, 2020.” Temperature records have been taken since 1890 in that location. I emphasize that because it is likely you will see a few headlines that say, “For the first time ever.” The NWS Tampa office is located in Ruskin, Florida. It would not surprise me if temperatures were even hotter in the highly urbanized parts of the region.

Central Florida always feels hot in July, and it is. But it has never, hit an official air temperature recorded in triple digits. The average high temperature at this time of year is in the low nineties. Temperatures in the region rarely exceed 95 degrees F, but the humidity can certainly elevate the “feels like” apparent temperature or heat index above 100 degrees F. Now imagine 100-degree air temperatures and the humidity. Though not the focus here, studies continue to confirm that as climate warms, the intensity and frequency of heat waves is changing too.

This presents challenges for people using old heat benchmarks like their childhood as a reference point. This is not your grandmother’s heat. Temperatures through the middle of the week will remain oppressive in Florida, and I would not be surprised if a few more records fall. Why is it so hot? A dominant high-pressure system is bringing historically-hot conditions to the entire southeastern U.S, and it will persist into the first part of the week. Many media outlets have fallen in love with the term “heat dome,” but as a meteorologist, I prefer to explain it in terms of meteorology and physics.

If you see that terminology, it is referring to an extensive area of high pressure and warm temperatures. The dome of high pressure is often associated with sinking air that contributes to hot, dry conditions. The sinking air warms through something called adiabatic compression. In the absence of rising motion, rainfall-producing clouds are limited under these conditions.

Tampa Bay is strongly influenced by its proximity to water. The Gulf has several influences on local weather and climate. It is a source of moisture that contributes to very humid conditions. It creates microclimates like the sea breeze circulation. Because the land warms up faster during the day, a sea breeze moves in from the water. The sea breeze often produces clouds and rainstorms. At night, the breeze system can reverse as land cools faster than the water. Such circulations happen because water has a larger heat capacity than the land. It’s the same reason sand is hot on a May beach day, but the water is still cool. Locations closer to the coast also have smaller temperature ranges.