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

Washington/Dulles International Airport, DC (KIAD)

Lat: 38.93°NLon: 77.45°WElev: 312ft.

Mostly Cloudy

79°F

26°C

Humidity 85%
Wind Speed SW 5 mph
Barometer 30.06 in (1017.5 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index83°F (28°C)
Last update 15 Jul 10:52 pm EDT
Extended Forecast for

Herndon VA

  • Tonight

    Tonight: Mostly cloudy, with a low around 73. Calm wind.

    Low: 73 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Showers and thunderstorms likely, mainly after 4pm. Partly sunny, with a high near 90. Heat index values as high as 100. South wind 5 to 9 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 90 °F

    Partly Sunny
    then T-storms
    Likely

  • Wednesday Night

    Wednesday Night: Showers and thunderstorms likely, mainly before 8pm. Mostly cloudy, with a low around 74. Southwest wind around 7 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 74 °F

    T-storms
    Likely then
    Slight Chance
    T-storms

  • Thursday

    Thursday: A chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 95. Heat index values as high as 103. West wind around 8 mph. Chance of precipitation is 40%.

    High: 95 °F

    Mostly Sunny
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 8pm. Partly cloudy, with a low around 75. Southwest wind 3 to 6 mph. Chance of precipitation is 30%.

    Low: 75 °F

    Chance
    T-storms then
    Partly Cloudy

  • Friday

    Friday: Showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 88. Chance of precipitation is 60%.

    High: 88 °F

    Partly Sunny
    then Showers
    Likely

  • Friday Night

    Friday Night: Showers likely and possibly a thunderstorm before 8pm. Mostly cloudy, with a low around 71. Chance of precipitation is 60%.

    Low: 71 °F

    Showers
    Likely then
    Partly Cloudy

  • Saturday

    Saturday: A chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 86. Chance of precipitation is 40%.

    High: 86 °F

    Partly Sunny
    then Chance
    T-storms

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 72. Chance of precipitation is 30%.

    Low: 72 °F

    Chance
    T-storms

Detailed Forecast

Tonight
Mostly cloudy, with a low around 73. Calm wind.
Wednesday
Showers and thunderstorms likely, mainly after 4pm. Partly sunny, with a high near 90. Heat index values as high as 100. South wind 5 to 9 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Wednesday Night
Showers and thunderstorms likely, mainly before 8pm. Mostly cloudy, with a low around 74. Southwest wind around 7 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Thursday
A chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 95. Heat index values as high as 103. West wind around 8 mph. Chance of precipitation is 40%.
Thursday Night
A chance of showers and thunderstorms before 8pm. Partly cloudy, with a low around 75. Southwest wind 3 to 6 mph. Chance of precipitation is 30%.
Friday
Showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 88. Chance of precipitation is 60%.
Friday Night
Showers likely and possibly a thunderstorm before 8pm. Mostly cloudy, with a low around 71. Chance of precipitation is 60%.
Saturday
A chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 86. Chance of precipitation is 40%.
Saturday Night
A chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 72. Chance of precipitation is 30%.
Sunday
Showers likely and possibly a thunderstorm, mainly after 2pm. Partly sunny, with a high near 89. Chance of precipitation is 70%.
Sunday Night
Showers and thunderstorms likely. Mostly cloudy, with a low around 71. Chance of precipitation is 60%.
Monday
A chance of showers and thunderstorms. Partly sunny, with a high near 86. Chance of precipitation is 50%.
Monday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 68. Chance of precipitation is 30%.
Tuesday
A chance of showers and thunderstorms. Partly sunny, with a high near 87. Chance of precipitation is 40%.
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ABOUT THIS FORECAST

 
Point Forecast:
Herndon VA
 38.97°N 77.38°W (Elev. 354 ft)
Last Update:
1:31 pm EDT Jul 15, 2025
Forecast Valid:
11pm EDT Jul 15, 2025-6pm EDT Jul 22, 2025
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

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National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation