Storm Station
Portola Valley, California
55° 70°/51°
Partly cloudy· Feels like 55°·Light air 2 mph SW
Mostly cloudy, with a low around 49. Southwest wind around 3 mph.
0UV Low
48Air quality
66%Humidity
56%Cloud
Now
12:15 AM
55feels55
now, partly cloudy
Today
Sep 27
7051
UV 6
overcast
Mon
Sep 28
7950
UV 6
overcast
Tue
Sep 29
8551
UV 6
mostly clear day
Wed
Sep 30
9057
UV 6
clear day
Thu
Oct 1
8857
UV 6
partly cloudy day
Fri
Oct 2
9157
UV 6
partly cloudy day
Sat
Oct 3
9664
UV 6
overcast
55°
70°51°
79°50°
85°51°
90°57°
88°57°
91°57°
96°64°

As of 12:15 AM in Portola Valley, California.

What is measuring near here

The 4 instruments nearest Portola Valley, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 1.1 miles away.

measured now2 instruments

Los Altos RAWSLOAC1

A remote fire weather station/4.4 mi away/479 ft/28 ft below here

temp, wind, gust, humidity, pressure

Rank266of 3,115

Palo Alto AirportPAO

At an airfield/8.1 mi away/7 ft/500 ft below here

temp, wind, gust, visibility, precip, pressure

Rank3,101of 3,115

measured daily2 instruments

Portola Valley 1.3 ENECA-SM-9

In a volunteer observer's own ground/1.1 mi away/531 ft/24 ft above here

precip, snowfall, snow depth

Rank-

Skyline Ridge PreserveSKYC1

In a park or preserve/4.7 mi away/2,253 ft/1,746 ft above here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Los Altos RAWS, drawn

The nearest instrument reporting now, 4.4 mi from Portola Valley. From its report of Sep 26, 2026, 11:10 PM local time: 3 of its 5 sheets.

The air

54.0 F with a dew point of 51.4 F, 91 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 600 ft up.

Chart of the air at Los Altos RAWS: temperature 54.0 degrees Fahrenheit and dew point 51.4, 91 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 600 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT LOAC1FIG. B THE AIR AT LOS ALTOS RAWSTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00040 F50 F60 FSATURATES 600 FT ABOVE THE STATION, AT 50.8 FTEMPERATURE AND DEW POINT 54.0 F, 51.4 FRELATIVE HUMIDITY 91 PER CENTTHE AIR COOLS ABOUT 5.4 F EACH 1,000 FT IT RISES, AND ITS DEW POINT ABOUT 1 FSOLID: THE LIFTED AIR'S TEMPERATURE; DASHED: ITS DEW POINTTITLELos Altos RAWS, the airSTATION REPORT · DCP LOAC1TYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 5DATE2026-09-27IDSR-LOAC1-1DRAWN AS linework on paperSOURCES FB-WAT-020, FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

Calm.

Plan of the wind at Los Altos RAWS, north up: calm; beside it the Beaufort scale from calm to hurricane force, force 0, calm, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT LOAC1FIG. C THE WIND AT LOS ALTOS RAWSPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONCALMBEAUFORT FORCELEAST WIND, MPH0CALM0NOW, 0 MPH1LIGHT AIR1GUST, 2 MPH2LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLELos Altos RAWS, the windSTATION REPORT · DCP LOAC1TYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 2 of 5DATE2026-09-27IDSR-LOAC1-2DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008

The column

At 479 ft above sea level, 2 per cent of the atmosphere's air lies below the station. The standard atmosphere puts the pressure there at 29.41 inHg and the temperature at 57.3 F; it reports 54.0 F, 3.3 F colder than standard.

Section from sea level of where Los Altos RAWS stands in the atmosphere, height to scale: the station 479 feet above sea level with 2 per cent of the air below it; the standard atmosphere's pressure there, 29.41 inches of mercury, and temperature, 57.3 degrees Fahrenheit.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT LOAC1FIG. D WHERE LOS ALTOS RAWS STANDS IN THE ATMOSPHERESECTION FROM SEA LEVEL, HEIGHT TO SCALE, THE STATION IN THE STANDARD ATMOSPHEREFT ABOVE SEA LEVEL05,00010,00015,000SEA LEVEL, 29.92 inHg IN THE STANDARD ATMOSPHERELOS ALTOS RAWS2 PER CENT OF THE AIR BELOW IT479 FT10 PER CENT OF THE AIR BELOW, 2,890 FT20 PER CENT OF THE AIR BELOW, 6,050 FT30 PER CENT OF THE AIR BELOW, 9,540 FT40 PER CENT OF THE AIR BELOW, 13,470 FTSTANDARD PRESSURE HERE29.41 inHgSTANDARD TEMPERATURE HERE57.3 FTEMPERATURE, REPORTED54.0 FTITLELos Altos RAWS, the columnSTATION REPORT · DCP LOAC1TYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 3 of 5DATE2026-09-27IDSR-LOAC1-3DRAWN AS linework on paperSOURCES FB-ENG-001, FB-ENG-003

The full report of Los Altos RAWS, in 5 sheets, each beside the Field Book plates that explain it

-in

Snow on the ground

Elsewhere in California

33 places, each with its own forecast and its own instruments.

Near Portola Valley

The nearest places, each with its own forecast and the instruments nearest it.