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

Hazardous Weather Conditions

Current conditions at

Washington/Dulles International Airport, DC (KIAD)

Lat: 38.93°NLon: 77.45°WElev: 312ft.

A Few Clouds

78°F

26°C

Humidity 87%
Wind Speed S 5 mph
Barometer 29.99 in (1015.2 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 8 Jul 1:52 am EDT
Extended Forecast for

Herndon VA

Flood Watch July 8, 02:00pm until July 9, 12:00am
Heat Advisory July 8, 01:00pm until July 8, 07:00pm
Click here for hazard details and duration
Flood Watch
Heat Advisory

  • Overnight

    Overnight: Partly cloudy, with a low around 73. Light west wind.

    Low: 73 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Scattered showers and thunderstorms, then showers and possibly a thunderstorm after 4pm. Some of the storms could produce heavy rainfall. High near 94. Heat index values as high as 102. Calm wind becoming southwest 5 to 7 mph in the afternoon. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

    High: 94 °F

    Mostly Sunny
    then Heavy
    Rain

  • Tuesday Night

    Tuesday Night: Showers and thunderstorms likely, mainly before 8pm. Some of the storms could produce heavy rainfall. Partly cloudy, with a low around 71. Northeast wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.

    Low: 71 °F

    Heavy Rain
    then Partly
    Cloudy

  • Wednesday

    Wednesday: Showers likely and possibly a thunderstorm after 2pm. Mostly sunny, with a high near 91. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 91 °F

    Mostly Sunny
    then Showers
    Likely

  • Wednesday Night

    Wednesday Night: Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am, then a slight chance of showers after 2am. Mostly cloudy, with a low around 71. South wind 3 to 5 mph. Chance of precipitation is 60%.

    Low: 71 °F

    Showers
    Likely

  • Thursday

    Thursday: A chance of showers before 11am, then a chance of showers and thunderstorms between 11am and 2pm, then showers and possibly a thunderstorm after 2pm. High near 88. Chance of precipitation is 80%.

    High: 88 °F

    Chance
    Showers then
    T-storms

  • Thursday Night

    Thursday Night: Showers and thunderstorms before 11pm, then a chance of showers between 11pm and 2am. Low around 70. Chance of precipitation is 80%.

    Low: 70 °F

    T-storms then
    Chance
    Showers

  • Friday

    Friday: Showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 90. Chance of precipitation is 60%.

    High: 90 °F

    Partly Sunny
    then Showers
    Likely

  • Friday Night

    Friday Night: Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. Mostly cloudy, with a low around 71. Chance of precipitation is 60%.

    Low: 71 °F

    Showers
    Likely then
    Chance
    T-storms

Detailed Forecast

Overnight
Partly cloudy, with a low around 73. Light west wind.
Tuesday
Scattered showers and thunderstorms, then showers and possibly a thunderstorm after 4pm. Some of the storms could produce heavy rainfall. High near 94. Heat index values as high as 102. Calm wind becoming southwest 5 to 7 mph in the afternoon. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.
Tuesday Night
Showers and thunderstorms likely, mainly before 8pm. Some of the storms could produce heavy rainfall. Partly cloudy, with a low around 71. Northeast wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.
Wednesday
Showers likely and possibly a thunderstorm after 2pm. Mostly sunny, with a high near 91. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Wednesday Night
Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am, then a slight chance of showers after 2am. Mostly cloudy, with a low around 71. South wind 3 to 5 mph. Chance of precipitation is 60%.
Thursday
A chance of showers before 11am, then a chance of showers and thunderstorms between 11am and 2pm, then showers and possibly a thunderstorm after 2pm. High near 88. Chance of precipitation is 80%.
Thursday Night
Showers and thunderstorms before 11pm, then a chance of showers between 11pm and 2am. Low around 70. Chance of precipitation is 80%.
Friday
Showers likely and possibly a thunderstorm after 2pm. Partly sunny, with a high near 90. Chance of precipitation is 60%.
Friday Night
Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. 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 90. Chance of precipitation is 50%.
Saturday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 72. Chance of precipitation is 30%.
Sunday
A chance of showers and thunderstorms. Partly sunny, with a high near 90. Chance of precipitation is 50%.
Sunday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 72. Chance of precipitation is 30%.
Monday
A chance of showers and thunderstorms. Partly sunny, with a high near 88. Chance of precipitation is 50%.
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ABOUT THIS FORECAST

 
Point Forecast:
Herndon VA
 38.97°N 77.38°W (Elev. 354 ft)
Last Update:
1:30 am EDT Jul 8, 2025
Forecast Valid:
2am EDT Jul 8, 2025-6pm EDT Jul 14, 2025
 
Forecast Discussion
 
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Additional Resources

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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