Storm Station
Sign in

Diamond Bar, California

City in Los Angeles County, California

Air quality

The air at Diamond Bar

Index 40, good, led by ozone. Read at 1 AM from its reporting area, E San Gabriel Vly (CA), 10 miles off.

40Good
  • Fine particles (PM2.5)7Good10.1 mi
  • Ozone40Good40 ppb9.2 mi
  • Coarse particles (PM10)17Good10.1 mi
  • Nitrogen dioxide1Good1.4 ppb9.2 mi
  • Sulfur dioxide0Good0.1 ppb20 mi
  • Carbon monoxide-0.3 ppm13.7 mi

The days ahead

Good each day through Today, led by ozone. Yesterday measured 16, good.

Smoke, the next 41 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 Diamond Bar

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 Diamond Bar, the next 41 hours

Visibility stays 10 miles or more through Sat 5 PM.

FriSat

On the radar over Diamond Bar, CaliforniaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Diamond Bar, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 2.9 miles away.

measured now4 instruments

measured daily2 instruments

Walnut 0.5 SSWCA-LA-120

In a volunteer observer's own ground/2.9 mi away/565 ft/476 ft below here

precip, snowfall, snow depth

Rank-

Covina YardCTFC1

At a cooperative observer's station/7.3 mi away/594 ft/447 ft below here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Tonner Canyon, drawn

The nearest instrument reporting now, 3.7 mi from Diamond Bar, California. From its report of Oct 16, 2026, 12:57 AM local time: 3 of its 5 sheets.

The air

79.0 F with a dew point of 35.7 F, 21 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 9,800 ft up.

Chart of the air at Tonner Canyon: temperature 79.0 degrees Fahrenheit and dew point 35.7, 21 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 9,800 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT TNRC1FIG. B THE AIR AT TONNER CANYONTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION02,0004,0006,0008,00010,00012,00020 F40 F60 F80 FSATURATES 9,800 FT ABOVE THE STATION, AT 26.8 FTEMPERATURE 79.0 FDEW POINT 35.7 FSPREAD 43.3 FRELATIVE HUMIDITY 21 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 POINTTITLETonner Canyon, the airSTATION REPORT · DCP TNRC1TYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 5DATE2026-10-16IDSR-TNRC1-1DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the east northeast (58 degrees) at 24 mph, gusting 50 mph: force 5, a fresh breeze on the Beaufort scale. The strongest gust today was 50 mph.

Plan of the wind at Tonner Canyon, north up: blowing from 58 degrees, the east northeast, at 24 miles an hour, gusting 50; beside it the Beaufort scale from calm to hurricane force, force 5, fresh breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT TNRC1FIG. C THE WIND AT TONNER CANYONPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 58°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE19NOW, 24 MPH6STRONG BREEZE257NEAR GALE328GALE399STRONG GALE47GUST, 50 MPH10STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLETonner Canyon, the windSTATION REPORT · DCP TNRC1TYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 2 of 5DATE2026-10-16IDSR-TNRC1-2DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008

The column

At 1,335 ft above sea level, 5 per cent of the atmosphere's air lies below the station. The standard atmosphere puts the pressure there at 28.51 inHg and the temperature at 54.2 F; it reports 79.0 F, 24.8 F warmer than standard.

Section from sea level of where Tonner Canyon stands in the atmosphere, height to scale: the station 1,335 feet above sea level with 5 per cent of the air below it; the standard atmosphere's pressure there, 28.51 inches of mercury, and temperature, 54.2 degrees Fahrenheit.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT TNRC1FIG. D WHERE TONNER CANYON 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 ATMOSPHERETONNER CANYON5 PER CENT OF THE AIR BELOW IT1,335 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 HERE28.51 inHgSTANDARD TEMPERATURE HERE54.2 FTEMPERATURE, REPORTED79.0 FTITLETonner Canyon, the columnSTATION REPORT · DCP TNRC1TYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 3 of 5DATE2026-10-16IDSR-TNRC1-3DRAWN AS linework on paperSOURCES FB-ENG-001, FB-ENG-003

The full report of Tonner Canyon, in 5 sheets, each beside the Field Book plates that explain it

-

Snow on the ground

Elsewhere in California

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

Near Diamond Bar

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

Near Diamond Bar

River and lake gauges