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.

A Few Clouds

86°F

30°C

Humidity 72%
Wind Speed E 6 mph
Barometer 30.03 in (1016.7 mb)
Dewpoint 76°F (24°C)
Visibility 10.00 mi
Heat Index96°F (36°C)
Last update 22 Aug 11:53 pm EDT
Extended Forecast for

26 Miles NNW Long Key FL

  • Overnight

    Overnight: Partly cloudy, with a low around 77. Calm wind.

    Low: 77 °F

    Partly Cloudy

  • Sunday

    Sunday: A slight chance of showers and thunderstorms before 10am, then a chance of showers and thunderstorms after 11am. Mostly sunny, with a high near 92. Heat index values as high as 103. Calm wind becoming south around 6 mph in the afternoon. Chance of precipitation is 40%.

    High: 92 °F

    Chance
    T-storms

  • Sunday Night

    Sunday Night: A 20 percent chance of showers and thunderstorms, mainly between 10pm and 11pm. Partly cloudy, with a low around 77. Calm wind.

    Low: 77 °F

    Slight Chance
    T-storms then
    Mostly Clear

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 7am. Mostly sunny, with a high near 92. Heat index values as high as 101. Calm wind becoming southeast 5 to 8 mph in the afternoon.

    High: 92 °F

    Slight Chance
    T-storms

  • Monday Night

    Monday Night: A 20 percent chance of showers and thunderstorms after 2am. Partly cloudy, with a low around 76. East wind around 5 mph becoming calm in the evening.

    Low: 76 °F

    Partly Cloudy
    then Slight
    Chance
    T-storms

  • Tuesday

    Tuesday: A 40 percent chance of showers and thunderstorms, mainly after 8am. Mostly sunny, with a high near 93. Southeast wind 3 to 7 mph.

    High: 93 °F

    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 79. East wind 7 to 9 mph.

    Low: 79 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Showers likely and possibly a thunderstorm before 2pm, then a chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 89. Southeast wind around 7 mph. Chance of precipitation is 60%.

    High: 89 °F

    Showers
    Likely

  • Wednesday Night

    Wednesday Night: A 30 percent chance of showers and thunderstorms, mainly after 2am. Mostly cloudy, with a low around 79. East wind around 9 mph.

    Low: 79 °F

    Chance
    Showers then
    Chance
    T-storms

Detailed Forecast

Overnight
Partly cloudy, with a low around 77. Calm wind.
Sunday
A slight chance of showers and thunderstorms before 10am, then a chance of showers and thunderstorms after 11am. Mostly sunny, with a high near 92. Heat index values as high as 103. Calm wind becoming south around 6 mph in the afternoon. Chance of precipitation is 40%.
Sunday Night
A 20 percent chance of showers and thunderstorms, mainly between 10pm and 11pm. Partly cloudy, with a low around 77. Calm wind.
Monday
A 20 percent chance of showers and thunderstorms after 7am. Mostly sunny, with a high near 92. Heat index values as high as 101. Calm wind becoming southeast 5 to 8 mph in the afternoon.
Monday Night
A 20 percent chance of showers and thunderstorms after 2am. Partly cloudy, with a low around 76. East wind around 5 mph becoming calm in the evening.
Tuesday
A 40 percent chance of showers and thunderstorms, mainly after 8am. Mostly sunny, with a high near 93. Southeast wind 3 to 7 mph.
Tuesday Night
A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 79. East wind 7 to 9 mph.
Wednesday
Showers likely and possibly a thunderstorm before 2pm, then a chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 89. Southeast wind around 7 mph. Chance of precipitation is 60%.
Wednesday Night
A 30 percent chance of showers and thunderstorms, mainly after 2am. Mostly cloudy, with a low around 79. East wind around 9 mph.
Thursday
A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89.
Thursday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 79.
Friday
A 50 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89.
Friday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 80.
Saturday
Showers and thunderstorms likely. Mostly sunny, with a high near 89. Chance of precipitation is 60%.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
26 Miles NNW Long Key FL
 25.19°N 80.94°W
Last Update:
7:46 pm EDT Aug 22, 2026
Forecast Valid:
12am EDT Aug 23, 2026-6pm EDT Aug 29, 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