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Mill Valley, California

City in Marin County, California

Air quality

The air at Mill Valley

Index 37, good, led by fine particles. Read at 3 AM from its reporting area, San Lorenzo Valley (CA), 61 miles off.

37Good
  • Fine particles (PM2.5)37Good-

The days ahead

Good each day through Wed Oct 21, led by ozone. Yesterday measured 25, good.

Smoke, the next 44 hours

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

SatSun

Precipitation

What has fallen at Mill Valley

None in the last 3 days, to Sat 3 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 Mill Valley, the next 44 hours

Visibility stays 10 miles or more through Sun 11 PM.

SatSun

On the radar over Mill Valley, CaliforniaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 5 instruments nearest Mill Valley, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 1.3 miles away.

measured now3 instruments

NovatoDVO

At an airfield/16.6 mi away/3 ft/54 ft below here

temp, wind, gust, visibility, precip, pressure

Rank25of 4,461

measured daily2 instruments

Mill Valley - Muir WoodsMUIC1

At a cooperative observer's station/1.6 mi away/850 ft/793 ft above here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Novato, drawn

The nearest airport reporting now, 16.6 mi from Mill Valley, California. From its report of Oct 17, 2026, 4:15 AM local time: 3 of its 6 sheets.

The sky

Overcast at 2,200 ft; the ceiling is 2,200 ft; visibility 10 mi or more.

Section of the sky over Novato, height above the station to scale: overcast cloud with its base at 2,200 feet, the ceiling at 2,200 feet, and visibility of 10 mi or more.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT DVOFIG. A THE SKY OVER NOVATOSECTION, 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 STATION05001,0001,5002,0002,5003,0003,500ETAGESLOWTHE STATIONTHE CEILOMETER READS TO 12,000 FT, ABOVE THIS SHEETOVC 2,200 FTOVERCAST, 8 EIGHTHS OF THE SKYCEILING 2,200 FTVISIBILITY, MILES: 10 MI OR MORE0510TITLENovato, the skySTATION REPORT · ASOS DVOTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-17IDSR-DVO-1DRAWN AS linework on paperSOURCES FB-SKY-001, FB-SKY-017, FB-SKY-016, FB-SKY-018

The air

50.0 F with a dew point of 44.6 F, 82 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 1,200 ft up; the lowest cloud reported is at 2,200 ft.

Chart of the air at Novato: temperature 50.0 degrees Fahrenheit and dew point 44.6, 82 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 1,200 feet above the station, against the lowest cloud reported at 2,200 feet; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT DVOFIG. B THE AIR AT NOVATOTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00030 F40 F50 F60 FSATURATES 1,200 FT ABOVE THE STATION, AT 43.4 FLOWEST CLOUD REPORTED, OVC 2,200 FTTEMPERATURE 50.0 FDEW POINT 44.6 FSPREAD 5.4 FRELATIVE HUMIDITY 82 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 POINTTITLENovato, the airSTATION REPORT · ASOS DVOTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-17IDSR-DVO-2DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

Calm.

Plan of the wind at Novato, 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 DVOFIG. C THE WIND AT NOVATOPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONCALMBEAUFORT FORCELEAST WIND, MPH0CALM0NOW, 0 MPH1LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLENovato, the windSTATION REPORT · ASOS DVOTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-17IDSR-DVO-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Novato, 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 Mill Valley

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

Near Mill Valley

River and lake gauges