National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

The Florida Keys - Marathon International Airport (KMTH)

Lat: 24.73°NLon: 81.05°WElev: 13ft.

Fair

84°F

29°C

Humidity 77%
Wind Speed Calm
Barometer 29.96 in (1014.3 mb)
Dewpoint 76°F (24°C)
Visibility 10.00 mi
Heat Index93°F (34°C)
Last update 2 Sep 6:53 am EDT
Extended Forecast for

25 Miles NNW Long Key FL

  • Today

    Today: A 40 percent chance of showers and thunderstorms, mainly after 5pm. Mostly sunny, with a high near 87. Heat index values as high as 100. Calm wind becoming south around 5 mph in the afternoon.

    High: 87 °F

    Chance
    T-storms

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms, mainly before 2am. Partly cloudy, with a low around 80. Light and variable wind becoming east around 5 mph.

    Low: 80 °F

    Chance
    T-storms

  • Thursday

    Thursday: A 30 percent chance of showers and thunderstorms, mainly between 1pm and 2pm. Mostly sunny, with a high near 88. Heat index values as high as 102. Light and variable wind becoming south around 6 mph in the afternoon.

    High: 88 °F

    Chance
    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 81. Southeast wind around 7 mph.

    Low: 81 °F

    Chance
    T-storms

  • Friday

    Friday: Showers likely and possibly a thunderstorm before 2pm, then showers and thunderstorms likely after 2pm. Mostly sunny, with a high near 87. Southeast wind around 8 mph. Chance of precipitation is 70%.

    High: 87 °F

    Showers
    Likely then
    T-storms
    Likely

  • Friday Night

    Friday Night: Showers and thunderstorms likely, mainly before 8pm. Partly cloudy, with a low around 80. East wind around 8 mph. Chance of precipitation is 60%.

    Low: 80 °F

    T-storms
    Likely

  • Saturday

    Saturday: Showers and thunderstorms likely. Mostly sunny, with a high near 87. Southeast wind around 6 mph. Chance of precipitation is 70%.

    High: 87 °F

    T-storms
    Likely

  • Saturday Night

    Saturday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 78. East wind around 5 mph becoming calm in the evening.

    Low: 78 °F

    Chance
    T-storms

  • Sunday

    Sunday: Showers likely and possibly a thunderstorm before 2pm, then a chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 90. Light and variable wind. Chance of precipitation is 60%.

    High: 90 °F

    Showers
    Likely

Detailed Forecast

Today
A 40 percent chance of showers and thunderstorms, mainly after 5pm. Mostly sunny, with a high near 87. Heat index values as high as 100. Calm wind becoming south around 5 mph in the afternoon.
Tonight
A 30 percent chance of showers and thunderstorms, mainly before 2am. Partly cloudy, with a low around 80. Light and variable wind becoming east around 5 mph.
Thursday
A 30 percent chance of showers and thunderstorms, mainly between 1pm and 2pm. Mostly sunny, with a high near 88. Heat index values as high as 102. Light and variable wind becoming south around 6 mph in the afternoon.
Thursday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 81. Southeast wind around 7 mph.
Friday
Showers likely and possibly a thunderstorm before 2pm, then showers and thunderstorms likely after 2pm. Mostly sunny, with a high near 87. Southeast wind around 8 mph. Chance of precipitation is 70%.
Friday Night
Showers and thunderstorms likely, mainly before 8pm. Partly cloudy, with a low around 80. East wind around 8 mph. Chance of precipitation is 60%.
Saturday
Showers and thunderstorms likely. Mostly sunny, with a high near 87. Southeast wind around 6 mph. Chance of precipitation is 70%.
Saturday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 78. East wind around 5 mph becoming calm in the evening.
Sunday
Showers likely and possibly a thunderstorm before 2pm, then a chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 90. Light and variable wind. Chance of precipitation is 60%.
Sunday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 78.
Labor Day
A 50 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
Monday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 78.
Tuesday
A 50 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
25 Miles NNW Long Key FL
 25.13°N 81.03°W
Last Update:
4:31 am EDT Sep 2, 2026
Forecast Valid:
7am EDT Sep 2, 2026-6pm EDT Sep 8, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation