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Keystone, South Dakota

Town in Pennington County, South Dakota

Air quality

The air at Keystone

Index 31, good, led by ozone. Read at 10 PM from its reporting area, Rapid City (SD), 15 miles off.

31Good
  • Fine particles (PM2.5)18Good23.9 mi
  • Ozone31Good34 ppb18.4 mi
  • Coarse particles (PM10)28Good18.4 mi

The days ahead

Yesterday measured 16, good.

Smoke, the next 44 hours

No smoke near the ground through Sat 6 PM.

FriSat

Precipitation

What has fallen at Keystone

None in the last 3 days, to Thu 9 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 Keystone, the next 44 hours

Visibility stays 10 miles or more through Sat 6 PM.

FriSat

On the radar over Keystone, South DakotaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Keystone, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 1.5 miles away.

measured now4 instruments

SD RWIS Three ForksSD067

Beside a road/6.1 mi away/4,731 ft/395 ft above here

temp, pavement temp, wind, visibility, precip

Rank-

CusterCUT

At an airfield/14.8 mi away/5,534 ft/1,198 ft above here

temp, wind, gust, visibility, precip, pressure

Rank668of 806

measured daily2 instruments

Keystone 5.9 ESESD-PN-110

In a volunteer observer's own ground/5.4 mi away/3,979 ft/357 ft below here

precip, snowfall, snow depth

Rank-

Station report

The weather at Custer, drawn

The nearest airport reporting now, 14.8 mi from Keystone, South Dakota. From its report of Oct 15, 2026, 9:53 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 Custer, 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 CUTFIG. A THE SKY OVER CUSTERSECTION, 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 MORE0510TITLECuster, the skySTATION REPORT · ASOS CUTTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-CUT-1DRAWN AS linework on paperSOURCES FB-SKY-001

The air

32.0 F with a dew point of 19.0 F, 58 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 2,900 ft up.

Chart of the air at Custer: temperature 32.0 degrees Fahrenheit and dew point 19.0, 58 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 2,900 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT CUTFIG. B THE AIR AT CUSTERTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,0004,00010 F20 F30 F40 FSATURATES 2,900 FT ABOVE THE STATION, AT 16.3 FTEMPERATURE 32.0 FDEW POINT 19.0 FSPREAD 13.0 FRELATIVE HUMIDITY 58 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 POINTTITLECuster, the airSTATION REPORT · ASOS CUTTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-CUT-2DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the north northwest (340 degrees) at 23 mph, gusting 46 mph: force 5, a fresh breeze on the Beaufort scale. The strongest gust today was 51 mph.

Plan of the wind at Custer, north up: blowing from 340 degrees, the north northwest, at 23 miles an hour, gusting 46; beside it the Beaufort scale from calm to hurricane force, force 5, fresh breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT CUTFIG. C THE WIND AT CUSTERPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 340°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE19NOW, 23 MPH6STRONG BREEZE257NEAR GALE328GALE39GUST, 46 MPH9STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLECuster, the windSTATION REPORT · ASOS CUTTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-CUT-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

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

0in

Snow on the ground

Measured at Mount Rushmore National Memorial (RNMS2), 1.8 miles from here, read 14 Oct, 23:59. measured daily

Elsewhere in South Dakota

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

Near Keystone

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

Near Keystone

River and lake gauges