National Weather Service Miami South Florida Heat Index Wednesday May 21, 2025
Miami, FL – The National Weather Service (NWS) in Miami has issued a forecast for dangerous and impactful heat expected to grip metro Miami-Dade, Broward, and Palm Beach counties on Wednesday afternoon, May 21, 2025.
The forecast warns of a significant heat risk for the region, with metro areas facing major to extreme heat conditions while most of South Florida will experience a moderate risk as Florida’s heat wave continues.
The NWS Miami graphic shows heat indices expected to reach between 100°F and 107°F in the most affected areas, driven in part by the urban heat island effect.
Cities impacted include:
Take action when you see symptoms of heat exhaustion and heat stroke.
To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air-conditioned environments.
Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1.
The urban heat island effect occurs when urban areas become much warmer—sometimes by as much as 20°F—than nearby rural landscapes, especially during summer.
According to NASA, this happens because cities have more heat-absorbing surfaces like asphalt, concrete, and buildings, and less vegetation to provide cooling through shade and evapotranspiration.
Copyright 2023-2025 FloridaWord.com
