Station Overview Station Location
Station Number CA-SM-9 Latitude 37.381892
Station Name Portola Valley 1.3 ENE Longitude -122.197612
County San Mateo Elevation (ft) 531



Month 30 Yr Avg by PRISM Total Prcp Sum Days Covered By All Observations Daily Prcp Sum Daily Observation Count Multiday Prcp Sum Days Covered by Multiday Observations Multiday Observation Count Days With Prcp Days With Trace Total Snowfall Days With Snowfall Days With Snow On Ground
Oct 11 1.19 1.50 30 1.50 21 0.00 9 2 6 2 0.0 0 0
Nov 11 2.99 1.59 25 1.59 20 0.00 5 2 10 2 0.0 0 0
Dec 11 4.80 0.14 29 0.10 20 0.04 9 2 3 0 0.0 0 0
Jan 12 5.34 3.30 22 3.30 19 0.00 3 1 5 1 0.0 0 0
Feb 12 5.03 0.77 25 0.74 18 0.03 7 1 5 2 0.0 0 0
March 12 4.20 6.63 28 5.77 24 0.86 4 2 15 0 0.0 0 0
April 12 1.71 2.99 22 2.99 22 0.00 0 0 7 2 0.0 0 0
May 12 0.63 0.02 26 0.02 11 0.00 15 1 1 0 0.0 0 0
June 12 0.16 0.14 15 0.14 4 0.00 11 2 1 1 0.0 0 0
July 12 0.03 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Aug 12 0.04 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Sept 12 0.21 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Water Year Totals: 26.33" 17.08" 222 days 16.15" 159 0.93" 63 days 13 53 days 10 days 0.0" 0 days 0 days



Days in Water Year Cell Color Key
        Daily Observation with Prcp         Missing Day
        Multiday Observation         Daily/Multiday Observation Conflict

Day of Year Daily Prcp Multiday Prcp
10/1/2011 0.00
10/2/2011 0.00
10/3/2011 0.00
10/4/2011 0.30
10/5/2011 0.80
10/6/2011 0.20
10/7/2011 0.15
10/8/2011 0.00
10/9/2011 0.00
10/10/2011 0.00
10/11/2011 0.03
10/12/2011 0.02
10/13/2011 0.00
10/14/2011 0.00
10/15/2011 0.00
10/16/2011 T
10/17/2011 **
10/18/2011 **
10/19/2011 **
10/20/2011 0.00
10/21/2011 T
10/22/2011
10/23/2011 0.00
10/24/2011
10/25/2011 0.00
10/26/2011 0.00
10/27/2011 0.00 **
10/28/2011 **
10/29/2011 **
10/30/2011 **
10/31/2011 0.00
11/1/2011
11/2/2011
11/3/2011
11/4/2011 0.18
11/5/2011 T
11/6/2011 0.30
11/7/2011 0.02
11/8/2011
11/9/2011 0.00
11/10/2011 0.00
11/11/2011 0.00
11/12/2011 0.26
11/13/2011 **
11/14/2011 0.00
11/15/2011 0.00
11/16/2011 **
11/17/2011 **
11/18/2011 T
11/19/2011 0.20
11/20/2011 0.55
11/21/2011 0.02
11/22/2011 0.00
11/23/2011
11/24/2011 T
11/25/2011 0.02
11/26/2011 0.00
11/27/2011 0.00
11/28/2011 0.02
11/29/2011 0.00
11/30/2011 0.02
12/1/2011 0.00
12/2/2011 0.00
12/3/2011 0.00
12/4/2011
12/5/2011 0.00
12/6/2011 0.00
12/7/2011 0.00
12/8/2011 0.00
12/9/2011 0.00
12/10/2011 0.00
12/11/2011 0.00
12/12/2011 0.03
12/13/2011
12/14/2011 0.00
12/15/2011 0.05
12/16/2011 0.02
12/17/2011 0.00 **
12/18/2011 **
12/19/2011 **
12/20/2011 **
12/21/2011 0.00
12/22/2011 0.00
12/23/2011
12/24/2011 0.00
12/25/2011 0.00
12/26/2011 0.00
12/27/2011 0.00
12/28/2011 **
12/29/2011 **
12/30/2011 **
12/31/2011 0.04
Day of YearDaily PrcpMultiday Prcp
1/1/2012 0.00
1/2/2012
1/3/2012 T
1/4/2012 0.00
1/5/2012
1/6/2012 0.00
1/7/2012 0.00
1/8/2012
1/9/2012 0.00
1/10/2012
1/11/2012 0.00
1/12/2012
1/13/2012 0.00
1/14/2012 0.00
1/15/2012 0.00
1/16/2012 0.00
1/17/2012
1/18/2012 0.00
1/19/2012
1/20/2012 0.10
1/21/2012 2.18
1/22/2012 0.05
1/23/2012 0.91
1/24/2012 0.06
1/25/2012
1/26/2012
1/27/2012 0.00
1/28/2012 **
1/29/2012 **
1/30/2012 T
1/31/2012 0.00
2/1/2012 T
2/2/2012
2/3/2012 0.00
2/4/2012
2/5/2012 0.00
2/6/2012 0.00
2/7/2012 0.08
2/8/2012 T
2/9/2012 0.00
2/10/2012 0.00
2/11/2012 0.06
2/12/2012 0.02
2/13/2012
2/14/2012 0.50
2/15/2012 0.08
2/16/2012 0.00
2/17/2012 0.00
2/18/2012 **
2/19/2012 **
2/20/2012 **
2/21/2012 0.03
2/22/2012 0.00
2/23/2012
2/24/2012 0.00
2/25/2012 0.00
2/26/2012 0.00
2/27/2012 **
2/28/2012 **
2/29/2012 **
3/1/2012 0.86
3/2/2012 0.56
3/3/2012 0.00
3/4/2012 0.00
3/5/2012 0.00
3/6/2012 0.03
3/7/2012 0.00
3/8/2012
3/9/2012 0.00 **
3/10/2012 **
3/11/2012 0.00
3/12/2012
3/13/2012 0.18
3/14/2012 0.68
3/15/2012 0.58
3/16/2012 0.10
3/17/2012 1.20
3/18/2012 0.10
3/19/2012 0.02
3/20/2012 0.00
3/21/2012
3/22/2012 0.00
3/23/2012 0.00
3/24/2012 0.08
3/25/2012 1.18
3/26/2012 0.18
3/27/2012 0.04
3/28/2012 0.80
3/29/2012 0.04
3/30/2012
3/31/2012 0.00
Day of YearDaily PrcpMultiday Prcp
4/1/2012 0.80
4/2/2012 T
4/3/2012
4/4/2012 T
4/5/2012 0.00
4/6/2012
4/7/2012
4/8/2012 0.00
4/9/2012 0.00
4/10/2012 0.03
4/11/2012 0.40
4/12/2012 0.44
4/13/2012 1.18
4/14/2012
4/15/2012 0.00
4/16/2012 0.00
4/17/2012
4/18/2012 0.00
4/19/2012
4/20/2012 0.00
4/21/2012
4/22/2012 0.00
4/23/2012 0.00
4/24/2012 0.00
4/25/2012
4/26/2012 0.10
4/27/2012 0.04
4/28/2012 0.00
4/29/2012 0.00
4/30/2012 0.00
5/1/2012
5/2/2012 0.00
5/3/2012 0.00
5/4/2012 0.02
5/5/2012 0.00
5/6/2012
5/7/2012 0.00
5/8/2012 0.00
5/9/2012 **
5/10/2012 **
5/11/2012 **
5/12/2012 **
5/13/2012 **
5/14/2012 **
5/15/2012 **
5/16/2012 0.00
5/17/2012 0.00
5/18/2012 0.00
5/19/2012 0.00
5/20/2012
5/21/2012 0.00
5/22/2012
5/23/2012
5/24/2012 0.00
5/25/2012 **
5/26/2012 **
5/27/2012 **
5/28/2012 **
5/29/2012 **
5/30/2012 **
5/31/2012 **
6/1/2012 **
6/2/2012 **
6/3/2012 0.00
6/4/2012 T
6/5/2012 0.14
6/6/2012 0.00
6/7/2012 **
6/8/2012 **
6/9/2012 **
6/10/2012 **
6/11/2012 **
6/12/2012 **
6/13/2012 **
6/14/2012 0.00
6/15/2012
6/16/2012
6/17/2012
6/18/2012
6/19/2012
6/20/2012
6/21/2012 0.00
6/22/2012
6/23/2012
6/24/2012
6/25/2012
6/26/2012
6/27/2012
6/28/2012
6/29/2012
6/30/2012
Day of YearDaily PrcpMultiday Prcp
7/1/2012
7/2/2012
7/3/2012
7/4/2012
7/5/2012
7/6/2012
7/7/2012
7/8/2012
7/9/2012
7/10/2012
7/11/2012
7/12/2012
7/13/2012
7/14/2012
7/15/2012
7/16/2012
7/17/2012
7/18/2012
7/19/2012
7/20/2012
7/21/2012
7/22/2012
7/23/2012
7/24/2012
7/25/2012
7/26/2012
7/27/2012
7/28/2012
7/29/2012
7/30/2012
7/31/2012
8/1/2012
8/2/2012
8/3/2012
8/4/2012
8/5/2012
8/6/2012
8/7/2012
8/8/2012
8/9/2012
8/10/2012
8/11/2012
8/12/2012
8/13/2012
8/14/2012
8/15/2012
8/16/2012
8/17/2012
8/18/2012
8/19/2012
8/20/2012
8/21/2012
8/22/2012
8/23/2012
8/24/2012
8/25/2012
8/26/2012
8/27/2012
8/28/2012
8/29/2012
8/30/2012
8/31/2012
9/1/2012
9/2/2012
9/3/2012
9/4/2012
9/5/2012
9/6/2012
9/7/2012
9/8/2012
9/9/2012
9/10/2012
9/11/2012
9/12/2012
9/13/2012
9/14/2012
9/15/2012
9/16/2012
9/17/2012
9/18/2012
9/19/2012
9/20/2012
9/21/2012
9/22/2012
9/23/2012
9/24/2012
9/25/2012
9/26/2012
9/27/2012
9/28/2012
9/29/2012
9/30/2012



Observation Date Observation Time Precipitation Snowfall Snowfall SWE Snow Depth Snow SWE Notes
10/1/2011 7:00 AM 0.00 0.0 M M M windy last evening; very cloudy am.
10/2/2011 7:00 AM 0.00 0.0 M M M
10/3/2011 7:00 AM 0.00 0.0 M M M
10/4/2011 7:00 AM 0.30 M M M M
10/5/2011 7:00 AM 0.80 M M M M
10/6/2011 7:00 AM 0.20 M M M M
10/7/2011 7:00 AM 0.15 M M M M
10/8/2011 7:00 AM 0.00 0.0 M M M
10/9/2011 7:00 AM 0.00 0.0 M M M super foggy this am warmer days
10/10/2011 7:00 AM 0.00 0.0 M M M
10/11/2011 7:00 AM 0.03 M M M M
10/12/2011 7:00 AM 0.02 M M M M
10/13/2011 7:00 AM 0.00 0.0 M M M
10/14/2011 7:00 AM 0.00 0.0 M M M
10/15/2011 7:00 AM 0.00 0.0 M M M
10/16/2011 7:00 AM T M M M M
10/21/2011 7:00 AM T M M M M super foggy again this am
10/23/2011 7:00 AM 0.00 0.0 M M M
10/25/2011 7:00 AM 0.00 0.0 M M M
10/26/2011 7:00 AM 0.00 0.0 M M M chilly temps, clear skies
10/27/2011 7:00 AM 0.00 0.0 M M M
11/4/2011 7:00 AM 0.18 M M M M
11/5/2011 7:00 AM T M M M M chilly,breezy day yesterday, cloudy 43 degrees this am
11/6/2011 7:00 AM 0.30 M M M M rain stopped before midnight, chilly and sunny now
11/7/2011 7:00 AM 0.02 M M M M
11/9/2011 7:00 AM 0.00 0.0 M M M
11/10/2011 7:00 AM 0.00 0.0 M M M
11/11/2011 7:00 AM 0.00 0.0 M M M
11/12/2011 7:00 AM 0.26 M M M M dripping rain all day yesterday; cloudy and misty this am.
11/15/2011 7:00 AM 0.00 0.0 M M M
11/19/2011 7:00 AM 0.20 M M M M
11/20/2011 7:00 AM 0.55 M M M M rained most of the night; clearing and cool now
11/21/2011 7:00 AM 0.02 M M M M
11/22/2011 7:00 AM 0.00 0.0 M M M
11/24/2011 7:00 AM T M M M M big rain storm never appeared---blue sky showing 7:30am
11/25/2011 7:00 AM 0.02 M M M M almost no rain from this storm--wet ground but thats all
11/26/2011 7:00 AM 0.00 0.0 M M M bright sunny morning
11/27/2011 7:00 AM 0.00 0.0 M M M
11/28/2011 7:00 AM 0.02 M M M M dense fog again this am--think the precip was really just condensation; not actual rain
11/29/2011 7:00 AM 0.00 0.0 M M M fog not as dense this morning
11/30/2011 7:00 AM 0.02 M M M M heavy mist this am
12/1/2011 7:00 AM 0.00 0.0 M M M fog is gone! blustery winds but super clear.
12/2/2011 7:00 AM 0.00 0.0 M M M winds calm, lovely clear sky
12/3/2011 7:00 AM 0.00 0.0 M M M still chilly, breezy and dry
12/5/2011 7:00 AM 0.00 0.0 M M M 35 degrees, very chilly, clear and no sign of rain
12/6/2011 7:00 AM 0.00 0.0 M M M 34 degrees---and still no rain in the forecast.
12/7/2011 7:00 AM 0.00 0.0 M M M 32 degrees, hazy
12/8/2011 7:00 AM 0.00 0.0 M M M chilly 43 degrees and smoggy again!
12/9/2011 7:00 AM 0.00 0.0 M M M
12/10/2011 7:00 AM 0.00 0.0 M M M chilly, hazy and dry!
12/11/2011 7:00 AM 0.00 0.0 M M M no rain so far today!
12/12/2011 7:00 AM 0.03 M M M M just a heavy drizzle--but at least it is moisture!
12/14/2011 7:00 AM 0.00 0.0 M M M continues chilly and dry!
12/15/2011 7:00 AM 0.05 M M M M a very light rain--but at least there is moisture!
12/16/2011 7:00 AM 0.02 M M M M
12/17/2011 7:00 AM 0.00 0.0 M M M temps in the 30's and dry!
12/22/2011 7:00 AM 0.00 0.0 M M M 29 degrees clear and dry
12/24/2011 7:00 AM 0.00 0.0 M M M
12/25/2011 7:00 AM 0.00 0.0 M M M 32 degrees; ice on car windshield. still DRY!
12/26/2011 7:00 AM 0.00 0.0 M M M foggy, chilly 33 degrees.
12/27/2011 7:00 AM 0.00 0.0 M M M less fog;but no rain
1/1/2012 7:00 AM 0.00 0.0 M M M bright sunny am
1/3/2012 7:00 AM T M M M M dense fog;moisture on the ground but no rain!
1/4/2012 7:00 AM 0.00 0.0 M M M
1/6/2012 7:00 AM 0.00 0.0 M M M
1/7/2012 7:00 AM 0.00 0.0 M M M
1/9/2012 7:00 AM 0.00 0.0 M M M temp 34 degrees; bright full moon and clear skies
1/11/2012 7:00 AM 0.00 0.0 M M M
1/13/2012 7:00 AM 0.00 0.0 M M M
1/14/2012 7:00 AM 0.00 0.0 M M M
1/15/2012 7:00 AM 0.00 0.0 M M M
1/16/2012 7:00 AM 0.00 0.0 M M M 30 degrees rain finally in the forecast
1/18/2012 7:00 AM 0.00 0.0 M M M
1/20/2012 7:00 AM 0.10 M M M M not much rain--hope for more with the next round
1/21/2012 7:00 AM 2.18 M M M M finally real rain!!
1/22/2012 7:00 AM 0.05 M M M M
1/23/2012 7:00 AM 0.91 M M M M super windy all night; less so now; very light drizzle at obs time.
1/24/2012 7:00 AM 0.06 M M M M clear sunny skies this am
1/27/2012 7:00 AM 0.00 0.0 M M M
1/31/2012 7:00 AM 0.00 0.0 M M M foggy and chilly!
2/1/2012 7:00 AM T M M M M ground slightly wet--must have misted overnight. clearing at 7am
2/3/2012 7:00 AM 0.00 0.0 M M M clear sunny morning
2/5/2012 7:00 AM 0.00 0.0 M M M
2/6/2012 7:00 AM 0.00 0.0 M M M cloudy
2/7/2012 7:00 AM 0.08 M M M M not much of a storm--some wind;little rain
2/8/2012 7:00 AM T M M M M not much of a storm
2/9/2012 7:00 AM 0.00 0.0 M M M clear,sunny morning
2/10/2012 7:00 AM 0.00 0.0 M M M
2/11/2012 7:00 AM 0.06 M M M M drizzly in the hills all yesterday afternoon--some rain overnight--more predicted thru monday--finally!
2/12/2012 7:00 AM 0.02 M M M M precipitation yesterday am--probably just low clouds
2/14/2012 7:00 AM 0.50 M M M M steady rain all day yesterday!
2/15/2012 7:00 AM 0.08 M M M M light rain overnight clearing this am
2/16/2012 7:00 AM 0.00 0.0 M M M
2/17/2012 7:00 AM 0.00 0.0 M M M high clouds --no rain this am--
2/22/2012 7:00 AM 0.00 0.0 M M M clear and sunny--here we go again--no rain in sight!
2/24/2012 7:00 AM 0.00 0.0 M M M
2/25/2012 7:00 AM 0.00 0.0 M M M
2/26/2012 7:00 AM 0.00 0.0 M M M
3/2/2012 7:00 AM 0.56 M M M M
3/3/2012 7:00 AM 0.00 0.0 M M M
3/4/2012 7:00 AM 0.00 0.0 M M M clear, sunny temps in the 70's!
3/5/2012 7:00 AM 0.00 0.0 M M M
3/6/2012 7:00 AM 0.03 M M M M didn't start raining until the middle of the night; clearing now but very windy (and chilly) at 44 degrees
3/7/2012 7:00 AM 0.00 0.0 M M M
3/9/2012 7:00 AM 0.00 0.0 M M M sunny and clear
3/13/2012 7:00 AM 0.18 M M M M hopefully several days of rain ahead!
3/14/2012 7:00 AM 0.68 M M M M wonderful soaking rain!
3/15/2012 7:00 AM 0.58 M M M M
3/16/2012 7:00 AM 0.10 M M M M a steady "mist" most of afternoon yesterday and overnight
3/17/2012 7:00 AM 1.20 M M M M heavy rain from around 8pm to 11pm last night; none now
3/18/2012 7:00 AM 0.10 M M M M temps around 40 degrees--windy but not much rain overnight
3/19/2012 7:00 AM 0.02 M M M M 39 degrees! ,slightly breezy but rain is clearing
3/20/2012 7:00 AM 0.00 0.0 M M M 49 degrees cloudy, no rain
3/22/2012 7:00 AM 0.00 0.0 M M M
3/23/2012 7:00 AM 0.00 0.0 M M M chilly , clear and calm
3/24/2012 7:00 AM 0.08 M M M M started raining overnight but not a heavy rain yet.
3/25/2012 7:00 AM 1.18 M M M M rained hard overnight;stopped around 4am. super foggy this am
3/26/2012 7:00 AM 0.18 M M M M steady rain yesterday afternoon;stopped around 4pm. chilly ,damp but sunny at time of observation
3/27/2012 7:00 AM 0.04 M M M M breezy,cloudy no rain yet
3/28/2012 7:00 AM 0.80 M M M M
3/29/2012 7:00 AM 0.04 M M M M no rain overnight--some showers early yesterday am
3/31/2012 7:00 AM 0.00 0.0 M M M super windy and cloudy but no rain yet
4/1/2012 7:00 AM 0.80 M M M M heavy rain yesterday am--then showers all day--bright,sunny,chilly this am
4/2/2012 7:00 AM T M M M M winds died down;cloud cover this am
4/4/2012 7:00 AM T M M M M
4/5/2012 7:00 AM 0.00 0.0 M M M chilly 35 degrees this am!
4/8/2012 7:00 AM 0.00 0.0 M M M
4/9/2012 7:00 AM 0.00 0.0 M M M
4/10/2012 7:00 AM 0.03 M M M M
4/11/2012 7:00 AM 0.40 M M M M sunny and clearing this am
4/12/2012 7:00 AM 0.44 M M M M light rain at 7am. big winds some rain overnight--but didn't produce much!
4/13/2012 7:00 AM 1.18 M M M M thunder and lighting all evening. some hail. windy and rainy again around 3am
4/15/2012 7:00 AM 0.00 0.0 M M M warmer and sunny!
4/16/2012 7:00 AM 0.00 0.0 M M M
4/18/2012 7:00 AM 0.00 0.0 M M M
4/20/2012 7:00 AM 0.00 0.0 M M M clear and warm!
4/22/2012 7:00 AM 0.00 0.0 M M M 95 degrees the past 2 days---down to the 80's today
4/23/2012 7:00 AM 0.00 0.0 M M M temps down to 60; fog and breezy--possibly rain later in the week--
4/24/2012 7:00 AM 0.00 0.0 M M M low lying fog and clouds--no precipitation
4/26/2012 7:00 AM 0.10 M M M M soft, gentle rain on and off all night; sun breaking thru 7am
4/27/2012 7:00 AM 0.04 M M M M
4/28/2012 7:00 AM 0.00 0.0 M M M
4/29/2012 7:00 AM 0.00 0.0 M M M
4/30/2012 7:00 AM 0.00 0.0 M M M foggy early then clear and sunny
5/2/2012 7:00 AM 0.00 0.0 M M M breezy and cool
5/3/2012 7:00 AM 0.00 0.0 M M M
5/4/2012 7:00 AM 0.02 M M M M just a few light sprinkle--sunny and clearing in am
5/5/2012 7:00 AM 0.00 0.0 M M M
5/7/2012 7:00 AM 0.00 0.0 M M M clear warm and sunny
5/8/2012 7:00 AM 0.00 0.0 M M M clear,warm and sunny
5/17/2012 7:00 AM 0.00 0.0 M M M
5/18/2012 7:00 AM 0.00 0.0 M M M
5/19/2012 7:00 AM 0.00 0.0 M M M
5/21/2012 7:00 AM 0.00 0.0 M M M
5/24/2012 7:00 AM 0.00 0.0 M M M
6/4/2012 7:00 AM T M M M M
6/5/2012 7:00 AM 0.14 M M M M nice soaking rain yesterday--clear and sunny this am
6/6/2012 7:00 AM 0.00 0.0 M M M
6/21/2012 7:00 AM 0.00 0.0 M M M



Start Date End Date & Time Duration in Days Precipitation Snow Depth Snow Depth SWE Notes
10/17/2011 10/20/2011 12:00 AM 4 0.00 M M
10/27/2011 10/31/2011 12:00 AM 5 0.00 M M
11/13/2011 11/14/2011 12:00 AM 2 0.00 M M
11/16/2011 11/18/2011 12:00 AM 3 T M M
12/17/2011 12/21/2011 12:00 AM 5 0.00 M M
12/28/2011 12/31/2011 5:00 PM 4 0.04 M M
1/28/2012 1/30/2012 6:00 PM 3 T M M we were away for a couple of days--not clear if the trace was only fog condensation
2/18/2012 2/21/2012 7:00 AM 4 0.03 M M very foggy this am
2/27/2012 3/01/2012 7:00 AM 4 0.86 M M
3/9/2012 3/11/2012 5:00 PM 3 0.00 M M
5/9/2012 5/16/2012 12:00 AM 8 0.00 M M
5/25/2012 6/03/2012 7:00 AM 10 0.00 M M
6/7/2012 6/14/2012 12:00 AM 8 0.00 M M



Observation Date Observation Time Notes Largest Stone Size Average Stone Size Smallest Stone Size Stone Consistency Duration Minutes Durration Accuracy Damage Timing More Rain than Hail Hail Started Largest Hail Started Angle of Impact Number of Stones on Pad Distance Between Stones on Pad Depth of Stones on Ground