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Rancho Cucamonga, California

City in San Bernardino County, California

Air quality

The air at Rancho Cucamonga

Index 39, good, led by ozone. Read at 9 PM from its reporting area, C San Bernardino (CA), 11 miles off.

39Good
  • Fine particles (PM2.5)16Good4.7 mi
  • Ozone39Good43 ppb4.7 mi
  • Coarse particles (PM10)32Good4.7 mi
  • Nitrogen dioxide13Good14.1 ppb4.4 mi
  • Sulfur dioxide0Good0.2 ppb4.7 mi
  • Carbon monoxide-0.2 ppm4.4 mi

The days ahead

Good each day through Fri Oct 16, led by ozone. Yesterday measured 47, good.

Smoke, the next 44 hours

Little smoke near the ground through Sat 5 PM: the index from smoke stays at 17 or under.

FriSat

Precipitation

What has fallen at Rancho Cucamonga

None in the last 3 days, to Thu 9 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 Rancho Cucamonga, the next 44 hours

Visibility stays 10 miles or more through Sat 5 PM.

FriSat

On the radar over Rancho Cucamonga, CaliforniaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Rancho Cucamonga, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 0.8 miles away.

measured now4 instruments

measured daily2 instruments

Rancho Cucamonga 0.9 WCA-SR-93

In a volunteer observer's own ground/0.8 mi away/1,353 ft/12 ft above here

precip, snowfall, snow depth

Rank-

Riverside Fire STN #3REVC1

At a cooperative observer's station/15.9 mi away/850 ft/491 ft below here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Ontario INTL Arpt, drawn

The nearest airport reporting now, 5.0 mi from Rancho Cucamonga, California. From its report of Oct 15, 2026, 8:53 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 Ontario INTL Arpt, 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 ONTFIG. A THE SKY OVER ONTARIO INTL ARPTSECTION, 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 MORE0510TITLEOntario INTL Arpt, the skySTATION REPORT · ASOS ONTTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-ONT-1DRAWN AS linework on paperSOURCES FB-SKY-001

The air

82.0 F with a dew point of 34.0 F, 18 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 10,800 ft up.

Chart of the air at Ontario INTL Arpt: temperature 82.0 degrees Fahrenheit and dew point 34.0, 18 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 10,800 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT ONTFIG. B THE AIR AT ONTARIO INTL ARPTTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION02,0004,0006,0008,00010,00012,00014,00010 F30 F50 F70 F90 FSATURATES 10,800 FT ABOVE THE STATION, AT 24.3 FTEMPERATURE 82.0 FDEW POINT 34.0 FSPREAD 48.0 FRELATIVE HUMIDITY 18 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 POINTTITLEOntario INTL Arpt, the airSTATION REPORT · ASOS ONTTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-ONT-2DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the east northeast (70 degrees) at 8 mph, gusting 24 mph: force 3, a gentle breeze on the Beaufort scale. The strongest gust today was 51 mph.

Plan of the wind at Ontario INTL Arpt, north up: blowing from 70 degrees, the east northeast, at 8 miles an hour, gusting 24; beside it the Beaufort scale from calm to hurricane force, force 3, gentle breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT ONTFIG. C THE WIND AT ONTARIO INTL ARPTPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 70°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE8NOW, 8 MPH4MODERATE BREEZE135FRESH BREEZE19GUST, 24 MPH6STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLEOntario INTL Arpt, the windSTATION REPORT · ASOS ONTTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-ONT-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Ontario INTL Arpt, 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 Rancho Cucamonga

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

Near Rancho Cucamonga

River and lake gauges