People in Pinellas County know the misery of their sweltering summers, and now, everyone else will know it, too.
The two most humid cities in the United States are Pinellas Park and St. Petersburg, according to an analysis by a London-based home product evaluation company.
The 20 most humid cities in the United States, in fact, are all from Florida, the analysis said — 17 from Southeast Florida, the two from Tampa Bay and one in Southwest Florida.
Released last week, the analysis by HouseFresh, using data from the private Minneapolis-based weather-tracking website Weather Spark, features Florida in a way that humidity studies in earlier years have not.
Florida accounts for four of the 10 most humid U.S. cities in a 2021 analysis by worldpopulationreview.com, with New Orleans, Jacksonville and Houston the top three. This study is limited to major urban centers.
In a 2020 analysis by Groundworks, another home product evaluator, no Florida cities appear in the top ten. That study’s top three humid cities: Port Arthur, Texas; Lake Charles, La.; and Brownsville, Texas.
If the two Pinellas County cities are, in fact, the most humid, blame the region’s unique geography — sandwiched between Tampa Bay on one side and the Gulf of Mexico on the other, said Jennifer Hubbard of the National Weather Service’s Tampa Bay office.
“Pinellas County is a peninsula on another peninsula, so we’re completely surrounded by water,” said Hubbard, who had not reviewed the HouseFresh analysis. “That tends to keep things pretty moist.”
Proximity to the water coupled with a lack of cooling, drying arctic air makes the Tampa Bay area more humid than other areas of the Southeast and the rest of the country, Hubbard said.
Most Florida cities atop the HouseFresh list lie along the state’s two giant humidity drivers, the Gulf of Mexico and the Atlantic Ocean.
HouseFresh also blames the humidity on wind patterns that spread moist air across Florida and the water released into the air from the vegetation prevalent across the peninsula. A mature oak tree, for example, will put about 500 gallons of water daily into the air through this process, known as transpiration, the company said.
Another factor in Florida’s humidity is that it is the only state among the lower 48 with both a tropical climate and a coral reef, HouseFresh said.
The HouseFresh analysis measures humidity comfort level using the dew point temperature, the level to which the air must be cooled in order for it to become saturated. The dew point determines whether perspiration will evaporate from the skin, cooling the body. Lower dew points feel drier, higher dew points feel more humid.
The analysis measures what portion of each city’s muggiest day reaches each of six humidity levels — miserable, oppressive, muggy, humid, comfortable and dry. All 20 Florida cities listed were labeled as “miserable” for at least 36 percent of the muggiest day.
The study says Pinellas Park was “miserable” 48.7 percent of its muggiest day, “oppressive” 49.6 percent and merely muggy 1.8 percent. A few miles to the south, St. Petersburg was “miserable” 48.1 percent of the day, “oppressive” 49.8 percent and muggy 2.1 percent.
The HouseFresh analysis included 18,830 cities across the globe. While Florida’s humidity may appear brutal, it’s comfortable compared to other parts of the world.
The most humid city was Patna, India, according to the analysis, with a “miserable” level at 99.2 percent. Other Indian cities follow just behind.
Those looking to escape muggy Florida can find respite in Rocky Mountain cities, where humidity is next to none, the analysis said. Or, if you’re willing to travel abroad, head to Höfn, Iceland, where even the muggiest day checks in as 99.1 percent “dry.”