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Walnut Creek, California

City in Contra Costa County, California

Air quality

The air at Walnut Creek

Index 49, good, led by fine particles. Read at 12 AM from its reporting area, Concord (CA), 4 miles off.

49Good
  • Fine particles (PM2.5)49Good-
  • Ozone23Good-

The days ahead

Highest moderate, Sat Oct 17, led by ozone. Yesterday measured 39, good.

Smoke, the next 41 hours

Little smoke near the ground through Sat 5 PM: the index from smoke stays at 11 or under.

FriSat

Precipitation

What has fallen at Walnut Creek

None in the last 3 days, to Fri 12 AM. Measured by radar and rain gauges, as water.

Last 24 hours
0.00in
Last 3 days
0.00in

Visibility

How far you can see at Walnut Creek, the next 41 hours

Visibility stays 10 miles or more through Sat 5 PM.

FriSat

On the radar over Walnut Creek, CaliforniaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Walnut Creek, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 1.0 miles away.

measured now4 instruments

Briones RAWSPLEC1

A remote fire weather station/4.3 mi away/1,369 ft/1,247 ft above here

temp, wind, gust, humidity, pressure

Rank734of 4,465

measured daily2 instruments

Diablo - Mount DiabloMDJC1

At a cooperative observer's station/6.9 mi away/3,102 ft/2,980 ft above here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Citizen station EW8430, drawn

The nearest instrument reporting now, 1.0 mi from Walnut Creek, California. From its report of undefined: 3 of its 4 sheets.

The wind

Calm.

Plan of the wind at Citizen station EW8430, 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 EW8430FIG. C THE WIND AT CITIZEN STATION EW8430PLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONCALMBEAUFORT FORCELEAST WIND, MPH0CALM0NOW, 0 MPH1LIGHT AIR1GUST, 1 MPH2LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLECitizen station EW8430, the windSTATION REPORT · CWOP EW8430TYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 1 of 4DATE2026-10-16IDSR-EW8430-1DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008

The column

At 164 ft above sea level, 1 per cent of the atmosphere's air lies below the station. The standard atmosphere puts the pressure there at 29.74 inHg and the temperature at 58.4 F; the station's altimeter setting of 30.05 inHg means its barometer reads 29.87 inHg; it reports 60.0 F, 1.6 F warmer than standard.

Section from sea level of where Citizen station EW8430 stands in the atmosphere, height to scale: the station 164 feet above sea level with 1 per cent of the air below it; the standard atmosphere's pressure there, 29.74 inches of mercury, and temperature, 58.4 degrees Fahrenheit; the altimeter setting of 30.05 and the station pressure it means, 29.87.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT EW8430FIG. D WHERE CITIZEN STATION EW8430 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 ATMOSPHERECITIZEN STATION EW84301 PER CENT OF THE AIR BELOW IT164 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 HERE29.74 inHgSTANDARD TEMPERATURE HERE58.4 FALTIMETER SETTING, REPORTED30.05 inHgITS BAROMETER READS29.87 inHgTEMPERATURE, REPORTED60.0 FTITLECitizen station EW8430, the columnSTATION REPORT · CWOP EW8430TYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 4DATE2026-10-16IDSR-EW8430-2DRAWN AS linework on paperSOURCES FB-ENG-001, FB-ENG-003

The sun

On Oct 16 the noon sun stands 43 degrees above the horizon at 37.90 N, and the day is 11 h 03 min long. Level ground there takes 68 per cent of the noon sunlight a surface facing the sun would.

Elevation of the noon sun at Citizen station EW8430, angles true: on Oct 16 it stands 43 degrees above the horizon, against 76 at the June solstice, 52 at the equinoxes and 29 at the December solstice; the day is 11 h 03 min long.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT EW8430FIG. E THE SUN AT CITIZEN STATION EW8430ELEVATION LOOKING WEST, SOUTH TO THE LEFT: THE NOON SUN ON THE DAY OF THE REPORT, AND AT THE SOLSTICES AND EQUINOXES; ANGLES TRUETHE STATIONJUNE SOLSTICE 76°EQUINOXES 52°DECEMBER SOLSTICE 29°OCT 16, 43°SOUTHANGLES TRUE; THE RAYS ARE OF ONE LENGTH AND DRAW DIRECTION ONLYDAY LENGTH 11 H 03 MINLEVEL GROUND TAKES 68 PER CENT OF THE NOON SUN A FACING SURFACE WOULDLATITUDE 37.90 N; THE SUN'S DECLINATION -9.1°TITLECitizen station EW8430, the sunSTATION REPORT · CWOP EW8430TYPEELEVATIONSCALEANGLES TRUEREVAS REPORTED SHEET 3 of 4DATE2026-10-16IDSR-EW8430-3DRAWN AS linework on paperSOURCES FB-ENG-007

The full report of Citizen station EW8430, in 4 sheets, each beside the Field Book plates that explain it

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Snow on the ground

Elsewhere in California

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

Near Walnut Creek

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

Near Walnut Creek

River and lake gauges