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Mercer Island, Washington

City in King County, Washington

Air quality

The air at Mercer Island

Index 61, moderate, led by fine particles. Read at 12 AM from its reporting area, Seattle-Bellevue-Kent Valley (WA), 5 miles off.

61Moderate
  • Fine particles (PM2.5)61Moderate-
  • Ozone1Good-
  • Coarse particles (PM10)23Good-

The days ahead

Good each day through Sat Oct 17, led by fine particles. Yesterday measured 32, good.

Smoke, the next 42 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 Mercer Island

None in the last 3 days, to Thu 11 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 Mercer Island, the next 42 hours

Visibility stays 7 miles or more through Sat 5 PM, lowest 8 miles Sat 5 AM.

FriSat

On the radar over Mercer Island, WashingtonReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Mercer Island, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 1.0 miles away.

measured now4 instruments

Seattle WFOSEAW1

At a river or reservoir gauge/8.0 mi away/33 ft/242 ft below here

temp, wind, gust, humidity, pressure

Rank256of 1,451

measured daily2 instruments

Mercer Island 1.2 NEWA-KG-315

In a volunteer observer's own ground/1.0 mi away/111 ft/164 ft below here

precip, snowfall, snow depth

Rank-

Seattle WaSEW

At a cooperative observer's station/8.1 mi away/24 ft/251 ft below here

snowfall, snow depth, precip, high, low

Rank-

Station report

The weather at Seattle/Boeing Fld, drawn

The nearest airport reporting now, 4.4 mi from Mercer Island, Washington. From its report of Oct 15, 2026, 11:53 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 Seattle/Boeing Fld, 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 BFIFIG. A THE SKY OVER SEATTLE/BOEING FLDSECTION, 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 MORE0510TITLESeattle/Boeing Fld, the skySTATION REPORT · ASOS BFITYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-BFI-1DRAWN AS linework on paperSOURCES FB-SKY-001

The air

52.0 F with a dew point of 50.0 F, 93 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 500 ft up.

Chart of the air at Seattle/Boeing Fld: temperature 52.0 degrees Fahrenheit and dew point 50.0, 93 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 500 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT BFIFIG. B THE AIR AT SEATTLE/BOEING FLDTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00040 F50 F60 FSATURATES 500 FT ABOVE THE STATION, AT 49.5 FTEMPERATURE AND DEW POINT 52.0 F, 50.0 FRELATIVE HUMIDITY 93 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 POINTTITLESeattle/Boeing Fld, the airSTATION REPORT · ASOS BFITYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-BFI-2DRAWN AS linework on paperSOURCES FB-WAT-020, FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

Calm.

Plan of the wind at Seattle/Boeing Fld, 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 BFIFIG. C THE WIND AT SEATTLE/BOEING FLDPLAN, 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 FORCE73TITLESeattle/Boeing Fld, the windSTATION REPORT · ASOS BFITYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-BFI-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Seattle/Boeing Fld, in 6 sheets, each beside the Field Book plates that explain it

-

Snow on the ground

Elsewhere in Washington

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

Near Mercer Island

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

Near Mercer Island

River and lake gauges