Storm Station
Alta Sierra, California
64°
Partly cloudy· Feels like 64°·Light air 1 mph ESE
Mostly cloudy. Low around 55, with temperatures rising to around 58 overnight. Wind around 0 mph.
-UV
-Air quality
43%Humidity
71%Cloud

What is measuring near here

The 5 instruments nearest Alta Sierra, 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 now3 instruments

Grass ValleyGSVC1

At a river or reservoir gauge/5.2 mi away/2,421 ft/179 ft above here

temp, wind, gust, humidity, pressure

Rank756of 3,118

Grass ValleyGOO

At an airfield/6.9 mi away/3,115 ft/873 ft above here

temp, wind, gust, visibility, precip, pressure

Rank1,921of 3,118

Hwy 80 at Blue CanyonCD025

Beside a road/21.5 mi away/5,312 ft/3,070 ft above here

temp, pavement temp, wind, visibility, precip

Rank2,580of 3,118

measured daily2 instruments

Grass Valley 6.3 SCA-NV-18

In a volunteer observer's own ground/0.8 mi away/2,125 ft/117 ft below here

precip, snowfall, snow depth

Rank-

Grass Valley No. 2GRAC1

At a cooperative observer's station/5.1 mi away/2,379 ft/137 ft above here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Grass Valley, drawn

The nearest airport reporting now, 6.9 mi from Alta Sierra. From its report of Sep 27, 2026, 1:55 AM local time: 3 of its 6 sheets.

The sky

A few clouds at 4,000 ft, broken at 4,700 ft, broken at 5,500 ft; the ceiling is 4,700 ft; visibility 10 mi or more.

Section of the sky over Grass Valley, height above the station to scale: a few clouds cloud with its base at 4,000 feet, broken cloud with its base at 4,700 feet, broken cloud with its base at 5,500 feet, the ceiling at 4,700 feet, and visibility of 10 mi or more.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT GOOFIG. A THE SKY OVER GRASS VALLEYSECTION, 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 STATION02,5005,0007,50010,000ETAGESLOWMIDDLETHE STATIONTHE CEILOMETER READS TO 12,000 FT, ABOVE THIS SHEETBKN 5,500 FTBROKEN, 5 TO 7 EIGHTHS OF THE SKYBKN 4,700 FTBROKEN, 5 TO 7 EIGHTHS OF THE SKYFEW 4,000 FTA FEW CLOUDS, 1 TO 2 EIGHTHS OF THE SKYCEILING 4,700 FTVISIBILITY, MILES: 10 MI OR MORE0510TITLEGrass Valley, the skySTATION REPORT · ASOS GOOTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-09-27IDSR-GOO-1DRAWN AS linework on paperSOURCES FB-SKY-001, FB-SKY-017, FB-SKY-016, FB-SKY-018

The air

62.6 F with a dew point of 41.0 F, 45 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 4,900 ft up; the lowest cloud reported is at 4,000 ft.

Chart of the air at Grass Valley: temperature 62.6 degrees Fahrenheit and dew point 41.0, 45 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 4,900 feet above the station, against the lowest cloud reported at 4,000 feet; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT GOOFIG. B THE AIR AT GRASS VALLEYTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,0004,0005,0006,0007,00030 F40 F50 F60 F70 FSATURATES 4,900 FT ABOVE THE STATION, AT 36.3 FLOWEST CLOUD REPORTED, FEW 4,000 FTTEMPERATURE 62.6 FDEW POINT 41.0 FSPREAD 21.6 FRELATIVE HUMIDITY 45 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 POINTTITLEGrass Valley, the airSTATION REPORT · ASOS GOOTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-09-27IDSR-GOO-2DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

Calm.

Plan of the wind at Grass Valley, 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 GOOFIG. C THE WIND AT GRASS VALLEYPLAN, 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 FORCE73TITLEGrass Valley, the windSTATION REPORT · ASOS GOOTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-09-27IDSR-GOO-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Grass Valley, in 6 sheets, each beside the Field Book plates that explain it

0in

Snow on the ground

Measured at Grass Valley No. 2 (GRAC1), 5.1 miles from here, read 26 Sep, 08:30. measured daily

Elsewhere in California

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

Near Alta Sierra

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