Florida Hot Springs: Warm Mineral Springs

Last updated on February 5th, 2020.

Hot Springs of Florida

Florida is home to thousands of beautiful, natural springs, but only a few are natural hot springs.

Because of its incredible underground geology, most springs in Florida remain a pleasant (chilly!) temperature all year ‘round. They’re warm enough to swim on warm winter days, and refreshingly cool during steamy summers.

List of Florida’s Hot Springs

  • Warm Mineral Spring
  • Little Salt Spring
  • Hot Mud Spring

Warm Mineral Spring

Warm Mineral Springs Vintage Photo Swimsuit Competition
A vintage photo of a swimsuit competition held at Warm Mineral Springs
Florida Hot Springs: Warm Mineral Springs
Warm Mineral Springs is one of only three known natural hot springs in Florida, and the only one with public access.

Warm Mineral Spring is the only hot spring in Florida that’s open to the public.

Although people call it a hot spring, that name is a bit generous. At 87 degrees, it’s more like a warm spring than a hot spring.

But, deep below the surface— approx. 200 feet— Warm Mineral Spring is a real, true hot spring in Florida. Geothermal heated water gushes from deep within the Earth at a genuinely hot 97 degrees F.

Warm Mineral Springs is an incredible place. People visit from all over the world to bathe in its mineral-rich waters. There’s a legend (unconfirmed) that Juan Ponce de León–you know, the guy who famously died while searching for a Fountain of Youth in Florida–may have been looking for Warm Mineral Springs.

Little Salt Spring

Florida Hot Spring: A Marine Archeologist Surfaces with Artifacts from Little Salt Spring
A marine archeologist surfaces with artifacts

Little Salt Spring is one of only a few hot springs in Florida, and one of only two located on land. It’s an important archeological site owned and managed by the University of Miami.

Little Salt Spring a fascinating spring, and has been the site of some amazing historical treasure finds, including rare human remains from the last ice age. Incredibly, some of the remains contained brain matter, scalp and hair. Because of its historical, archeological and geological significance Little Salt Spring is managed as a private research site, which is not open to the public.

Florida History: Warm Mineral Spring Archeological Discovery
Wilburn “Sonny” Cockrell, a Florida State University archaeologist, displays a pre-historic human skull recovered from Warm Mineral Spring

Hot Mud Hole Spring

Hot Mud Spring is an amazing Florida hot spring. But unless you’re a fisherman or a scuba diver, it’s not accessible. Like Warm Mineral Spring it’s found deep underwater, miles offshore on the bottom of the Gulf of Mexico.

Like Warm Mineral Spring, Hot Mud Spring is hot because the spring system runs deep enough to be warmed by the Earth’s geothermal core. And like Warm Mineral Spring, the underwater vent discharges hot spring water (97F) that’s unusually rich with nutrients and minerals.

Fishing and Scuba Diving

The warm temperature and rich concentration of nutrients, minerals and microscopic life supports a thriving undersea ecosystem. Mud Hole Spring is home to large fish, sharks, turtles and other sea life. It’s one of two important grazing areas in the Gulf of Mexico where loggerhead sea turtles come to forage– the other being the amazing Flower Garden Banks. Mud Hole Spring’s abundance of sea life makes it a popular destination for scuba divers and fishermen.

Mud Hole Location

Latitude 2615’48″N longitude 8201’06″W

The submarine hot spring vent is approximately 18.5 KM south of Sanibel Island Light House.

What causes spring water temperature?

Florida Spring temperatures depend on a few factors:

  1. Latitude
  2. Ground Temperature
  3. Depth underground
  4. Recent rain conditions

Latitude

Spring water temperature is a few degrees warmer in south Florida, and a few degrees cooler in north Florida.

The sun’s power is greatest at the equator. Land close to the equator absorbs more of the sun’s heat and energy, which makes the ground warmer. Spring water is stored underground, so it takes on the temperature of the ground.

The temperature of most Florida Springs is between 66 F and 97 F. That’s a big range, but most are on the cooler side. North Florida spring temperatures stay around 70 degrees. Central Florida spring water is about 75 degrees.

Ground Temperature and Depth Underground

If a spring system is deep enough it can be warmed by heat from the Earth’s inner core, creating a geothermal hot spring.

Spring-water temperatures range from 66 to 97 °F. The temperature of spring water in north Florida averages about 70 °F and about 75 °F in central Florida. Higher water temperatures in some Florida springs indicate that the water originates from deeper parts of the Floridan aquifer system. For example, the temperature of water discharging from Mud Hole Spring, a submarine spring located off the southwest coast of Florida, is about 97 °F.

Source: “Underground Florida: A Fieldtrip Guidebook of the West Central Florida karst” published by the University of South Florida Scholar Commons

Sources:

American Association of Petroleum Geologists 

American Water Resources Association 

Master’s Research Thesis: Geomorphology of Submarine Spring West of Fort Myers, Florida Shihadah M. Saleem, University of South Florida

Nature.Org: Florida Springs

USGS Mud Hole

Gulf Coast Association of Geological Societies

Mud Hole Spring Wikipedia