• Today

    Apr 21

    61°Lo 52°

    Mostly cloudy and breezy

    Low ragweed pollen levels
    • Grass
      Pollen
      0 - Low
    • Ragweed
      Pollen
      0 - Low
    • Tree
      Pollen
      350 - High
    more
  • Wed

    Apr 22

    69°Lo 50°

    Warmer

    Low ragweed pollen levels
    • Grass
      Pollen
      0 - Low
    • Ragweed
      Pollen
      0 - Low
    • Tree
      Pollen
      350 - High
    more
  • Thu

    Apr 23

    64°Lo 48°

    Breezy with some sun

    Low ragweed pollen levels
    • Grass
      Pollen
      0 - Low
    • Ragweed
      Pollen
      0 - Low
    • Tree
      Pollen
      350 - High
  • Fri

    Apr 24

    63°Lo 46°

    Partly sunny and breezy

    Low ragweed pollen levels
    • Precip
      7%
    • Wind
      Speed
      17 mph
    • Cloud
      Cover
      43%
    more
  • Sat

    Apr 25

    67°Lo 49°

    Partly sunny

    Ragweed Pollen Weather
    • Precip
      2%
    • Wind
      Speed
      10 mph
    • Cloud
      Cover
      26%
    more
Next Previous
< Previous 8 hours Next 8 hours >
  Thu
9am
10am 11am 12pm 1pm 2pm 3pm 4pm
  9am 10am 11am 12pm 1pm 2pm 3pm 4pm
Forecast
Partly Sunny
Partly Sunny
Partly Sunny
Partly Sunny
Partly Sunny
Partly Sunny
Partly Sunny
Partly Sunny
Temp (°F) 55° 56° 58° 61° 63° 64° 63° 61°
RealFeel® 52° 56° 59° 62° 64° 67° 64° 60°
Humidity 72% 68% 64% 60% 57% 55% 57% 60%
   
  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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0%
 
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0%
Ice
 
0%
 
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  9am 10am 11am 12pm 1pm 2pm 3pm 4pm
Wind (mph) 12 WSW 13 WSW 14 WSW 16 WSW 17 WSW 15 W 15 W 16 W
UV Index 2 4 6 7 7 7 6 4
Cloud Cover 45% 45% 45% 45% 45% 45% 45% 45%
Dew Point 46° 46° 46° 47° 48° 48° 48° 47°
Middle Grid line 65 F Middle Grid line 60 F Middle Grid line 55 F Middle Grid line 50 F

Temperature History - Apr 23

more Historical Weather Data >
  Today Normal Record 4/23/2014
High 64° N/A N/A 65°
Low 48° N/A N/A 40°

Sunrise/Sunset

Sunrise / Sunset Illustration

Rises at 6:23 AM with 13:28 of sunlight, then sets at 7:51 PM

Moonrise/Moonset

Astronomy >
Moonrise / Moonset Illustration

Rises at 10:35 AM with 14:22 of moolight, then sets at 12:57 AM

Castro Valley Weather Report

San Francisco: Clouds, Showers to Linger Ahead of Weekend

April 21, 2015; 6:20 AM ET

While cloudy conditions can be expected over the San Francisco area for the next several days, showers will not make a return until the middle of the week. more >

Thu. Dust & Dander

Thu. Wind Maps