• Tonight

    Apr 18

    Lo 49°

    Mainly clear

    Snow Days Weather
    • Snow
      0%
    • Ice
      0%
    • Snow
      0 in
  • Sun

    Apr 19

    75°Lo 49°

    Low clouds break for some sun

    Very Unlikely for a snow day
    • Snow
      0%
    • Ice
      0%
    • Snow
      0 in
    more
  • Mon

    Apr 20

    70°Lo 51°

    Partly sunny and nice

    Very Unlikely for a snow day
    • Snow
      0%
    • Ice
      0%
    • Snow
      0 in
    more
  • Tue

    Apr 21

    65°Lo 51°

    Partly sunny and breezy

    Very Unlikely for a snow day
    • Snow
      0%
    • Ice
      0%
    • Snow
      0 in
    more
  • Wed

    Apr 22

    68°Lo 49°

    A couple of showers possible

    Very Unlikely for a snow day
    • Snow
      0%
    • Ice
      0%
    • Snow
      0 in
    more
Next Previous
< Previous 8 hours Next 8 hours >
  Sat
10pm
11pm Sun
12am
1am 2am 3am 4am 5am
  10pm 11pm 12am 1am 2am 3am 4am 5am
Forecast
Partly Cloudy
Partly Cloudy
Partly Cloudy
Partly Cloudy
Mostly Clear
Mostly Clear
Mostly Clear
Mostly Clear
Temp (°F) 56° 54° 53° 53° 52° 52° 51° 50°
RealFeel® 52° 52° 51° 51° 52° 52° 51° 51°
Humidity 80% 82% 84% 85% 86% 86% 88% 89%
   
  10pm 11pm 12am 1am 2am 3am 4am 5am
Rain
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
Snow
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
Ice
 
0%
 
0%
 
0%
 
0%
 
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0%
   
  10pm 11pm 12am 1am 2am 3am 4am 5am
Wind (mph) 8 WNW 7 WNW 6 WNW 5 WNW 5 WNW 4 WNW 4 WNW 4 WNW
UV Index 0 0 0 0 0 0 0 0
Cloud Cover 41% 37% 35% 31% 29% 25% 25% 25%
Dew Point 49° 49° 48° 48° 48° 48° 47° 47°
Middle Grid line 60 F Middle Grid line 55 F Middle Grid line 50 F Middle Grid line 45 F

Temperature History - Apr 18

more Historical Weather Data >
  Today Normal Record 4/18/2014
High 73° N/A N/A 64°
Low 49° N/A N/A 49°

Sunrise/Sunset

Sunrise / Sunset Illustration

Rises at 6:29 AM with 13:18 of sunlight, then sets at 7:47 PM

Moonrise/Moonset

Astronomy >
Moonrise / Moonset Illustration

Rises at 6:32 AM with 13:29 of moolight, then sets at 8:01 PM

Castro Valley Weather Report

San Francisco: Pleasant Conditions to Hold into New Week

April 18, 2015; 10:41 PM ET

The Bay area will see pleasant conditions hold into the new week with plenty of sunshine and comfortable temperatures. more >

The 540 Snow Line

Dec 20, 2012; 5:00 AM ET The 540 line is often used by meteorologists to determine the chances of rain vs. snow.

48 Hour Precipitation Forecast

Sat. Snow Day Potential