It's not just you. It's hot out there — dangerously hot.
Heat index advisories have been issued for the entire state of Florida with heat index values of 110-115 expected for July 21 as a heat dome spreads across the South, forecasters said. Temperatures across most of the state are expected to be in the 90s and may approach 100 degrees around Orlando and Southwest Florida, forecasters said.
July 21 is also the one-year anniversary of the hottest day on record for the Earth.
North Florida and the Panhandle (and parts of southeast Alabama and southern Georgia) are under a heat advisory from 11 a.m. ET through 7 p.m., with heat index values up to 112 expected. Advisories for Central, Southwest and South Florida are scheduled for noon through 6 p.m., with heat index values from 109 to 112 possible.
The National Weather Service's Heat Risk map shows roughly two-thirds of Florida from the Panhandle down into the Central and Southwest regions facing major heat risk, with pockets of extreme heat risks in the Big Bend area and parts of the Southwest.
"The 'Dog Days of Summer' are in full swing for most of the eastern two-thirds of the Lower 48," Peter Mullinax with the NOAA/NWS Weather Prediction Center said in a Monday morning update. "This is brought about by a strengthening heat dome originating over the Deep South that builds in over the Mississippi and Ohio Valleys by mid-week.
"Expect some localized daily record highs to be broken in the Southeast," he said.
How hot will it be in Okaloosa County?
More details are below. The National Weather Service forecast for July 21 has Fort Walton Beach under a heat advisory from 10 a.m. to 7 p.m., with a high temperature near 93 and a heat index as high as 107. There is a 30% chance of rain, mainly between 1 and 4 p.m.
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Heat index alert: Weather watches and warnings issued in Florida
How dangerous is the heat in Florida?
When your body gets hot, it cools itself off by sweating. If you get too hot, you can't cool off fast enough and your brain, your heart, and other organs can be damaged.
If the relative humidity is high (that's the moisture in the atmosphere), your sweat doesn't evaporate as quickly — or at all — and you heat up even faster. That leads to dehydration, heat cramps, heat exhaustion, and potentially fatal heat stroke.
Anyone can get heat stroke, but infants, the elderly, and people with chronic disease, or people who have suffered from heat stroke in the past are at higher risk because their bodies may not be able to regulate temperature effectively.
Heat waves kill more people in the U.S. than hurricanes, tornadoes and floods combined, despite being more preventable. According to the CDC, the average number of heat-related deaths per year in the U.S. has risen 95% from 2010 to 2022. Florida saw an 88% increase in heat-related deaths from 2020 to 2023.
Symptoms, what to do, when to call 911
Heat advisory issued for Panhandle. Heat index up to 110
A heat advisory will be in effect from 10 a.m. CT to 7 p.m., National Weather Service Mobile said, with heat index values up to 108 expected.
Heat advisory issued for Tallahassee, Big Bend area. Heat index up to 112
A heat advisory is in effect for the North Florida region July 21 from 11 a.m. to 7 p.m. ET.
Heat index values are expected to reach 112 in portions of southeast Alabama, the Big Bend and Panhandle of Florida, and south central and southwest Georgia.
Heat advisory issued for Ocala, North Central Florida. Heat index up to 110
A heat advisory was issued for Northeast Florida for July 21, in effect from noon ET to 6 p.m.
Heat index values up to 110 expected for all of northeast and north central Florida and southeast Georgia, the National Weather Service Jacksonville said.
Heat advisory issued for Central Florida, East Coast. Heat index up to 112
A heat advisory has been issued for Lake, Volusia, Seminole, Orange, Osceola, Brevard, Okeechobee, Indian River, St Lucie, and Martin counties from noon to 6 p.m. ET July 21. Heat index values from 108 to 112 expected, the National Weather Service Melbourne said.
Heat advisory issued for Southwest Florida. Heat index could be 109
A heat advisory has been issued for portions of southwest and west central Florida from noon to 6 p.m. ET July 21. Heat index values up to 109 expected.
Heat advisory issued for South Florida. Heat index from 105 to 110
The National Weather Service issued a heat advisory for South Florida from noon July 12 until 6 p.m.
The heat index could reach between 105 and 110 across portions of southeast, south and southwest Florida and could reach even higher is some isolated locations, the National Weather Service said.
A major heat risk means there is a risk for heat-related illnesses for most residents, especially for those without access to air conditioning or who don't stay hydrated.
Heat advisory issued for Palm Beach County as temperatures and humidity soar
Heat index and temperature map for US, Florida
What is the heat index?
The heat index is what the temperature feels like to the human body when relative humidity is combined with the air temperature, according to the National Weather Service.
At its most basic: the heat index is what the temperature feels like when you're outside.
The chart above shows the combination of air temperature with humidity. It's important to note the chart uses the air temperature in the shade. In direct sun, the air temperature can be up to 15 degrees higher.
In Florida, except for Miami-Dade County, the National Weather Services offices around the state would issue a heat advisory if the heat index is expected to reach 108 to 112 degrees. The National Weather Service Miami said Miami/Dade County wanted a lower threshold for an advisory for its population, which was set at 105 degrees.
NWS issues several types of heat-related warnings
National Weather Service changed its heat watch and warning terms in March 2025. Here's what you should know:
? See when heat watches and warnings could be issued in your area
What is a heat advisory?
A heat advisory is issued for dangerous heat conditions that are not expected to reach warning criteria, according to the National Weather Service.
"Residents are advised to consider postponing or rescheduling outdoor activities, especially during the heat of the day. If you must be outside, be sure to drink plenty of water and take frequent breaks in the shade. Stay in a cool place, especially during the heat of the day and evening."
When a heat advisory is issued also depends on where you are in Florida.
For most of the state, a heat advisory is issued if the heat index is expected to be between 108 to 112 degrees.
Here is the breakdown by each NWS region. A heat advisory is issued when the heat index is expected to be:
The National Weather Service Miami said Miami/Dade County wanted a lower threshold for a heat advisory for its population.
Signs, symptoms of heat stroke
Heat stroke is the most serious of heat-related illnesses, according to the Centers for Disease Control. Signs and symptoms include:
What to do:
Signs, symptoms of heat exhaustion
Heat exhaustion is the body's response to an excessive loss of water and salt, usually through excessive sweating, the CDC said. Signs and symptoms include:
What to do:
How to stay safe. What do meteorologists recommend when it's hot outside?
? What's the best temperature to set your air conditioner thermostat?
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Jim Ross contributed