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South Monrovia Island, California

Community in Los Angeles County, California

Air quality

The air at South Monrovia Island

Index 43, good, led by ozone. Read at 8 PM from its reporting area, E San Gabriel Vly (CA), 6 miles off.

43Good
  • Fine particles (PM2.5)16Good-
  • Ozone43Good-
  • Coarse particles (PM10)15Good-

The days ahead

Good each day through Fri Oct 16, led by ozone. Yesterday measured 49, good.

Smoke, the next 46 hours

Little smoke near the ground through Sat 5 PM: the index from smoke stays at 22 or under.

ThuFriSat

Precipitation

What has fallen at South Monrovia Island

None in the last 3 days, to Thu 7 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 South Monrovia Island, the next 46 hours

Visibility stays 10 miles or more through Sat 5 PM.

ThuFriSat

On the radar over South Monrovia Island, CaliforniaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest South Monrovia Island, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 1.2 miles away.

measured now4 instruments

El MonteEMT

At an airfield/3.5 mi away/295 ft/106 ft below here

temp, wind, gust, visibility, precip, pressure

Rank4,211of 4,465

measured daily2 instruments

Arcadia 1.3 ESECA-LA-142

In a volunteer observer's own ground/1.2 mi away/403 ft/2 ft above here

precip, snowfall, snow depth

Rank-

San Gabriel Canyon PhGABC1

At a cooperative observer's station/5.5 mi away/1,040 ft/639 ft above here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Santa Fe Dam RAWS, drawn

The nearest instrument reporting now, 2.8 mi from South Monrovia Island, California. From its report of Oct 15, 2026, 7:57 PM local time: 3 of its 5 sheets.

The air

86.0 F with a dew point of 33.0 F, 15 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 11,900 ft up.

Chart of the air at Santa Fe Dam RAWS: temperature 86.0 degrees Fahrenheit and dew point 33.0, 15 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 11,900 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT STFC1FIG. B THE AIR AT SANTA FE DAM 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 STATION02,0004,0006,0008,00010,00012,00014,00010 F30 F50 F70 F90 FSATURATES 11,900 FT ABOVE THE STATION, AT 22.4 FTEMPERATURE 86.0 FDEW POINT 33.0 FSPREAD 53.0 FRELATIVE HUMIDITY 15 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 POINTTITLESanta Fe Dam RAWS, the airSTATION REPORT · DCP STFC1TYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 5DATE2026-10-16IDSR-STFC1-1DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the east northeast (76 degrees) at 7 mph, gusting 25 mph: force 2, a light breeze on the Beaufort scale. The strongest gust today was 25 mph.

Plan of the wind at Santa Fe Dam RAWS, north up: blowing from 76 degrees, the east northeast, at 7 miles an hour, gusting 25; beside it the Beaufort scale from calm to hurricane force, force 2, light breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT STFC1FIG. C THE WIND AT SANTA FE DAM RAWSPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 76°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE4NOW, 7 MPH3GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE25GUST, 25 MPH7NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLESanta Fe Dam RAWS, the windSTATION REPORT · DCP STFC1TYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 2 of 5DATE2026-10-16IDSR-STFC1-2DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008

The column

At 518 ft above sea level, 2 per cent of the atmosphere's air lies below the station. The standard atmosphere puts the pressure there at 29.37 inHg and the temperature at 57.2 F; it reports 86.0 F, 28.8 F warmer than standard.

Section from sea level of where Santa Fe Dam RAWS stands in the atmosphere, height to scale: the station 518 feet above sea level with 2 per cent of the air below it; the standard atmosphere's pressure there, 29.37 inches of mercury, and temperature, 57.2 degrees Fahrenheit.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT STFC1FIG. D WHERE SANTA FE DAM 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 ATMOSPHERESANTA FE DAM RAWS2 PER CENT OF THE AIR BELOW IT518 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 HERE29.37 inHgSTANDARD TEMPERATURE HERE57.2 FTEMPERATURE, REPORTED86.0 FTITLESanta Fe Dam RAWS, the columnSTATION REPORT · DCP STFC1TYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 3 of 5DATE2026-10-16IDSR-STFC1-3DRAWN AS linework on paperSOURCES FB-ENG-001, FB-ENG-003

The full report of Santa Fe Dam RAWS, in 5 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 South Monrovia Island

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

Near South Monrovia Island

River and lake gauges