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Grafton, Illinois

City in Jersey County, Illinois

Air quality

The air at Grafton

Index 15, good, led by fine particles. Read at 4 AM from its reporting area, Saint Louis (MO), 28 miles off.

15Good
  • Fine particles (PM2.5)15Good24.8 mi
  • Ozone-19 ppb5 mi
  • Coarse particles (PM10)7Good25 mi
  • Nitrogen dioxide2Good2.6 ppb12.9 mi
  • Sulfur dioxide0Good0.3 ppb15.1 mi
  • Carbon monoxide-0.1 ppm24.8 mi

The days ahead

Yesterday measured 40, good.

Smoke, the next 46 hours

No smoke near the ground through Sun 1 AM.

FriSat

Precipitation

What has fallen at Grafton

1.85 in in the last 24 hours, 2.15 in over the last 3 days, to Fri 3 AM. Measured by radar and rain gauges, as water.

Last 24 hours
1.85in
Last 3 days
2.15in

Visibility

How far you can see at Grafton, the next 46 hours

Visibility stays 10 miles or more through Sun 1 AM.

FriSat

On the radar over Grafton, IllinoisReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Grafton, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 8.8 miles away.

measured now4 instruments

measured daily2 instruments

JerseyvilleJVLI2

At a cooperative observer's station/10.0 mi away/610 ft/98 ft above here

snowfall, snow depth, precip, high, low

Rank1,215of 1,393

Station report

The weather at Alton/St Louis R, drawn

The nearest airport reporting now, 21.6 mi from Grafton, Illinois. From its report of Oct 16, 2026, 4:15 AM local time: 3 of its 6 sheets.

The sky

Overcast at 11,000 ft; the ceiling is 11,000 ft; visibility 10 mi or more.

Section of the sky over Alton/St Louis R, height above the station to scale: overcast cloud with its base at 11,000 feet, the ceiling at 11,000 feet, and visibility of 10 mi or more.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT ALNFIG. A THE SKY OVER ALTON/ST LOUIS RSECTION, 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 STATION02,5005,0007,50010,00012,50015,00017,500ETAGESLOWMIDDLEHIGHTHE STATIONTHE CEILOMETER READS TO 12,000 FTOVC 11,000 FTOVERCAST, 8 EIGHTHS OF THE SKYCEILING 11,000 FTVISIBILITY, MILES: 10 MI OR MORE0510TITLEAlton/St Louis R, the skySTATION REPORT · ASOS ALNTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-ALN-1DRAWN AS linework on paperSOURCES FB-SKY-001, FB-SKY-013, FB-SKY-014

The air

55.4 F with a dew point of 48.6 F, 78 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 1,600 ft up; the lowest cloud reported is at 11,000 ft.

Chart of the air at Alton/St Louis R: temperature 55.4 degrees Fahrenheit and dew point 48.6, 78 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 1,600 feet above the station, against the lowest cloud reported at 11,000 feet; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT ALNFIG. B THE AIR AT ALTON/ST LOUIS RTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,0004,0005,0006,0007,00040 F50 F60 F70 FSATURATES 1,600 FT ABOVE THE STATION, AT 47.1 FABOVE THIS SHEET: LOWEST CLOUD REPORTED, OVC 11,000 FTTEMPERATURE 55.4 FDEW POINT 48.6 FSPREAD 6.8 FRELATIVE HUMIDITY 78 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 POINTTITLEAlton/St Louis R, the airSTATION REPORT · ASOS ALNTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-ALN-2DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the west northwest (300 degrees) at 13 mph, gusting 20 mph: force 4, a moderate breeze on the Beaufort scale. The strongest gust today was 26 mph.

Plan of the wind at Alton/St Louis R, north up: blowing from 300 degrees, the west northwest, at 13 miles an hour, gusting 20; beside it the Beaufort scale from calm to hurricane force, force 4, moderate breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT ALNFIG. C THE WIND AT ALTON/ST LOUIS RPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 300°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE13NOW, 13 MPH5FRESH BREEZE19GUST, 20 MPH6STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLEAlton/St Louis R, the windSTATION REPORT · ASOS ALNTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-ALN-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

The full report of Alton/St Louis R, in 6 sheets, each beside the Field Book plates that explain it

0in

Snow on the ground

Measured at Jerseyville (JVLI2), 10.0 miles from here, read 13 Oct, 07:00. measured daily

Elsewhere in Illinois

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

Near Grafton

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

Near Grafton

River and lake gauges