• Today

    Aug 3

    72°Lo 62°

    Clouds, then sun

    Excellent for biking
    • Precip
      2%
    • Hours of Precip
      0
    • Wind
      Gust
      21 mph
    more
  • Tue

    Aug 4

    73°Lo 59°

    Low clouds, then some sun

    Excellent for biking
    • Precip
      7%
    • Hours of Precip
      0
    • Wind
      Gust
      20 mph
  • Wed

    Aug 5

    77°Lo 56°

    Low clouds, then sunshine

    Excellent for biking
    • Precip
      3%
    • Hours of Precip
      0
    • Wind
      Gust
      15 mph
    more
  • Thu

    Aug 6

    79°Lo 58°

    Partly sunny and pleasant

    Excellent for biking
    • Precip
      2%
    • Hours of Precip
      0
    • Wind
      Gust
      15 mph
    more
  • Fri

    Aug 7

    77°Lo 61°

    Low clouds, then some sun

    Excellent for biking
    • Precip
      6%
    • Hours of Precip
      0
    • Wind
      Gust
      22 mph
    more
Next Previous
< Previous 8 hours Next 8 hours >
  Tue
9am
10am 11am 12pm 1pm 2pm 3pm 4pm
  9am 10am 11am 12pm 1pm 2pm 3pm 4pm
Forecast
Cloudy
Cloudy
Cloudy
Cloudy
Cloudy
Mostly Sunny
Mostly Sunny
Mostly Sunny
Temp (°F) 63° 65° 66° 68° 70° 71° 72° 73°
RealFeel® 63° 66° 68° 72° 73° 75° 74° 74°
Humidity 79% 75% 72% 68% 62% 59% 58% 59%
   
  9am 10am 11am 12pm 1pm 2pm 3pm 4pm
Rain
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
 
0%
Snow
 
0%
 
0%
 
0%
 
0%
 
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Ice
 
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  9am 10am 11am 12pm 1pm 2pm 3pm 4pm
Wind (mph) 8 W 8 W 8 W 9 W 10 W 13 W 14 W 15 W
UV Index 1 2 3 5 6 8 6 5
Cloud Cover 95% 95% 95% 95% 95% 26% 26% 26%
Dew Point 57° 56° 57° 57° 56° 56° 56° 58°
Middle Grid line 75 F Middle Grid line 70 F Middle Grid line 65 F Middle Grid line 60 F

Temperature History - Aug 4

more Historical Weather Data >
  Today Normal Record 8/4/2014
High 73° N/A N/A 70°
Low 59° N/A N/A 57°

Sunrise/Sunset

Sunrise / Sunset Illustration

Rises at 6:14 AM with 14:00 of sunlight, then sets at 8:14 PM

Moonrise/Moonset

Astronomy >
Moonrise / Moonset Illustration

Rises at 11:07 PM with 13:11 of moolight, then sets at 12:18 PM

Castro Valley Weather Report

San Francisco: Seasonable Conditions to Persist Through Week

August 3, 2015; 10:50 AM ET

Dry and seasonable conditions will continue across the San Francisco Bay area this week. more >

Is Your Outdoor Gear Waterproof?

Dec 5, 2012; 5:00 AM ET Now that it's cold enough to hit the slopes, you may want to look more closely at what materials your winter sports gear is made of. As it turns out, not all waterproofing is created equal.