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

Dangerous Heat and Heavy Rainfall into the Weekend

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley into this weekend. Heat Advisories remain in effect. Heavy to excessive rainfall occurring at times through the weekend could bring areas of flooding to parts of the northern Rockies, upper Midwest, central Great Lakes, and southern New England. Read More >

Current conditions at

Napa, Napa County Airport (KAPC)

Lat: 38.2075°NLon: 122.27944°WElev: 33.0ft.

Mist

50°F

10°C

Humidity 100%
Wind Speed N 0 MPH
Barometer 30.14 in (1020.66 mb)
Dewpoint 50°F (10°C)
Visibility 0.25 mi
Last update 18 Sep 07:20 AM PDT
Extended Forecast for

4 Miles E Saint Helena CA

  • Today

    Today: Areas of fog before 9am. Otherwise, sunny, with a high near 84. Calm wind becoming west around 5 mph in the afternoon.

    High: 84 °F

    Areas Fog
    then Sunny

  • Tonight

    Tonight: Patchy fog after 3am. Otherwise, mostly clear, with a low around 53. Calm wind.

    Low: 53 °F

    Clear then
    Patchy Fog

  • Saturday

    Saturday: Patchy fog before 8am. Otherwise, sunny, with a high near 88. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 88 °F

    Patchy Fog
    then Sunny

  • Saturday Night

    Saturday Night: Patchy fog after 3am. Otherwise, partly cloudy, with a low around 52. West southwest wind around 5 mph becoming calm in the evening.

    Low: 52 °F

    Mostly Clear
    then Patchy
    Fog

  • Sunday

    Sunday: Areas of fog before 9am. Otherwise, partly sunny, with a high near 83. Calm wind becoming south southwest around 5 mph in the afternoon.

    High: 83 °F

    Areas Fog
    then Partly
    Sunny

  • Sunday Night

    Sunday Night: Patchy fog after midnight. Otherwise, mostly cloudy, with a low around 51.

    Low: 51 °F

    Mostly Cloudy
    then Patchy
    Fog

  • Monday

    Monday: Areas of fog before 9am. Otherwise, mostly sunny, with a high near 84.

    High: 84 °F

    Areas Fog
    then Sunny

  • Monday Night

    Monday Night: Patchy fog after midnight. Otherwise, mostly clear, with a low around 51.

    Low: 51 °F

    Mostly Clear
    then Patchy
    Fog

  • Tuesday

    Tuesday: Areas of fog before 9am. Otherwise, mostly sunny, with a high near 87.

    High: 87 °F

    Areas Fog
    then Sunny

Detailed Forecast

Today
Areas of fog before 9am. Otherwise, sunny, with a high near 84. Calm wind becoming west around 5 mph in the afternoon.
Tonight
Patchy fog after 3am. Otherwise, mostly clear, with a low around 53. Calm wind.
Saturday
Patchy fog before 8am. Otherwise, sunny, with a high near 88. Calm wind becoming southwest around 5 mph in the afternoon.
Saturday Night
Patchy fog after 3am. Otherwise, partly cloudy, with a low around 52. West southwest wind around 5 mph becoming calm in the evening.
Sunday
Areas of fog before 9am. Otherwise, partly sunny, with a high near 83. Calm wind becoming south southwest around 5 mph in the afternoon.
Sunday Night
Patchy fog after midnight. Otherwise, mostly cloudy, with a low around 51.
Monday
Areas of fog before 9am. Otherwise, mostly sunny, with a high near 84.
Monday Night
Patchy fog after midnight. Otherwise, mostly clear, with a low around 51.
Tuesday
Areas of fog before 9am. Otherwise, mostly sunny, with a high near 87.
Tuesday Night
Mostly clear, with a low around 53.
Wednesday
Mostly sunny, with a high near 92.
Wednesday Night
Partly cloudy, with a low around 56.
Thursday
Mostly sunny, with a high near 90.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
4 Miles E Saint Helena CA
 38.5°N 122.4°W (Elev. 476 ft)
Last Update:
1:26 am PDT Sep 18, 2026
Forecast Valid:
7am PDT Sep 18, 2026-6pm PDT Sep 24, 2026
 
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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