• Today

    Sep 17

    79°Lo 66°

    Mostly sunny

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

    Sep 18

    77°Lo 64°

    Partly sunny

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

    Sep 19

    77°Lo 61°

    Mostly sunny and pleasant

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

    Sep 20

    76°Lo 61°

    Plenty of sunshine

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

    Sep 21

    75°Lo 60°

    Plenty of sunshine

    Very Unlikely for a snow day
    • Snow
      0%
    • Ice
      0%
    • Snow
      0 in
    more
Next Previous
Hi 79° RealFeel® 78° Precipitation 15%

Day

N

E

S

W

  • W 9 mph
  • Gusts: 15 mph

Mostly sunny

  • Max UV Index: 6 (High)
  • Thunderstorms: 3%
  • Precipitation: 0 in
  • Rain: 0 in
  • Snow: 0 in
  • Ice: 0 in
  • Hours of Precipitation: 0 hrs
  • Hours of Rain: 0 hrs
Lo 66° RealFeel® 62° Precipitation 25%

Night

N

E

S

W

  • SW 7 mph
  • Gusts: 10 mph

Partly cloudy

  • Max UV Index: N/A
  • Thunderstorms: 4%
  • Precipitation: 0 in
  • Rain: 0 in
  • Snow: 0 in
  • Ice: 0 in
  • Hours of Precipitation: 0 hrs
  • Hours of Rain: 0 hrs

Temperature History - Sep 17

more Historical Weather Data >
  Today Normal Record 9/17/2013
High 79° N/A N/A 71°
Low 66° N/A N/A 58°

Sunrise/Sunset

Sunrise / Sunset Illustration

Rises at 6:52 AM with 12:21 of sunlight, then sets at 7:13 PM

Moonrise/Moonset

Astronomy >
Moonrise / Moonset Illustration

Rises at 1:01 AM with 14:21 of moolight, then sets at 3:22 PM

Top Story

Castro Valley Weather Report

San Francisco: Sunshine, Seasonable Temperatures to Continue

September 17, 2014; 7:35 AM ET

The Bay Area will continue to feature sunshine and seasonable temperatures as the summer season comes to a close. 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

Wed. Snow Day Potential