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Castle Hill, California

Community in Contra Costa County, California

Air quality

The air at Castle Hill

Index 46, good, led by ozone. Read at 5 PM from its reporting area, Concord (CA), 6 miles off.

46Good
  • Fine particles (PM2.5)35Good12.9 mi
  • Ozone46Good42 ppb12.9 mi
  • Nitrogen dioxide13Good14.5 ppb12.9 mi
  • Sulfur dioxide0Good0.5 ppb12.9 mi
  • Carbon monoxide-0.3 ppm12.9 mi

The days ahead

Highest 58, moderate, Sat Oct 17, led by ozone. Yesterday measured 54, moderate.

Smoke, the next 42 hours

Little smoke near the ground through Sun 11 AM: the index from smoke stays at 11 or under.

FriSatSun

Precipitation

What has fallen at Castle Hill

None in the last 3 days, to Fri 5 PM. 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 Castle Hill, the next 42 hours

Visibility stays 10 miles or more through Sun 11 AM.

FriSatSun

On the radar over Castle Hill, CaliforniaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Castle Hill, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 0.4 miles away.

measured now4 instruments

measured daily2 instruments

Walnut Creek 2.4 SWCA-CC-49

In a volunteer observer's own ground/0.4 mi away/243 ft/24 ft below here

precip, snowfall, snow depth

Rank-

Diablo - Mount DiabloMDJC1

At a cooperative observer's station/7.2 mi away/3,102 ft/2,835 ft above here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Concord/Buchanan, drawn

The nearest airport reporting now, 7.9 mi from Castle Hill, California. From its report of Oct 16, 2026, 4:53 PM local time: 3 of its 6 sheets.

The sky

No cloud below 12,000 ft; visibility 10 mi or more.

Section of the sky over Concord/Buchanan, height above the station to scale: no cloud detected below 12,000 feet, the reach of its ceilometer, and visibility of 10 mi or more.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT CCRFIG. A THE SKY OVER CONCORD/BUCHANANSECTION, HEIGHT ABOVE THE STATION TO SCALE, EACH LAYER AT THE HEIGHT OF ITS BASE AS REPORTED; COVER IN EIGHTHS OF THE SKY; TOPS NOT MEASUREDFT ABOVE THE STATION05001,0001,5002,0002,5003,000ETAGESLOWTHE STATIONTHE CEILOMETER READS TO 12,000 FT, ABOVE THIS SHEETNO CLOUD DETECTED BELOW 12,000 FTVISIBILITY, MILES: 10 MI OR MORE0510TITLEConcord/Buchanan, the skySTATION REPORT · ASOS CCRTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-CCR-1DRAWN AS linework on paperSOURCES FB-SKY-001

The air

89.0 F with a dew point of 33.0 F, 14 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 12,600 ft up.

Chart of the air at Concord/Buchanan: temperature 89.0 degrees Fahrenheit and dew point 33.0, 14 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 12,600 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT CCRFIG. B THE AIR AT CONCORD/BUCHANANTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION02,0004,0006,0008,00010,00012,00014,00016,00010 F30 F50 F70 F90 FSATURATES 12,600 FT ABOVE THE STATION, AT 21.9 FTEMPERATURE 89.0 FDEW POINT 33.0 FSPREAD 56.0 FRELATIVE HUMIDITY 14 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 POINTTITLEConcord/Buchanan, the airSTATION REPORT · ASOS CCRTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-CCR-2DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the north (360 degrees) at 5 mph: force 2, a light breeze on the Beaufort scale.

Plan of the wind at Concord/Buchanan, north up: blowing from 360 degrees, the north, at 5 miles an hour; beside it the Beaufort scale from calm to hurricane force, force 2, light breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT CCRFIG. C THE WIND AT CONCORD/BUCHANANPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 360°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE4NOW, 5 MPH3GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLEConcord/Buchanan, the windSTATION REPORT · ASOS CCRTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-CCR-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Concord/Buchanan, in 6 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 Castle Hill

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

Near Castle Hill

River and lake gauges