A glance at a chart of average temperatures in South Florida during the summer months reveals only that it gets into the 90s during the daytime in July, August and September, and cools off at night. This belies the reality—that this “average” is compiled by periods of gorgeous summer days, as well as stretches of heat and humidity that rival the Brazilian rain forest for sheer physical discomfort.
This is because Florida is in the path of air streams from the Gulf of Mexico, which bring the humidity—and also the summer storms, some of which might be big enough to cause major damage. There’s also the matter of topography. “Florida's humid climate is attributed to the fact that no point in the state is more than 60 miles from salt water, and no more than 345 feet above sea level,” writes Dawn Henthorn of GoFlorida.com.
The swath of the state from Orlando down to Fort Myers is known as the “lightning belt,” and with good reason. “Florida is the thunderstorm capital of the United States,” Henthorn says. All summer, the threat of the sudden outburst of these storms is all too real—and can have dire consequences. “Lightning is the state's leading cause of weather-related death, and the state has the distinction of having the nation's worst record of deaths by lightning.”
And still, in a state with such powerful bolts of lightning, the heat is even more of a killer. “In Florida, more people die from excessive heat than from lightning,” Henthorn says. “The human body temperature rises dangerously when hot days combine with high relative humidity, because perspiration cannot evaporate and cool the body.”
It’s a Hot One
And in Fort Lauderdale, Boca Raton, Boyton Beach and other hotspots in South Florida, the relative humidity—a ratio of temperature to moisture in the air—is always high during the summer months. “The warmer the air becomes, the more moisture it can hold,” Henthorn explains. “Therefore, a person can feel the humidity on a warm day with 80 percent humidity than on a cold day with the same humidity.”