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Cortland, Illinois

Town in DeKalb County, Illinois

Air quality

The air at Cortland

Index 22, good, led by fine particles. Read at 10 PM from its reporting area, Aurora and Elgin (IL), 15 miles off.

22Good
  • Fine particles (PM2.5)22Good-
  • Ozone11Good-

The days ahead

Good each day through Mon Oct 19, led by fine particles. Yesterday measured 28, good.

Smoke, the next 46 hours

No smoke near the ground through Sat 7 PM.

FriSat

Precipitation

What has fallen at Cortland

0.37 in in the last 24 hours, 0.96 in over the last 3 days, to Thu 9 PM. Measured by radar and rain gauges, as water.

Last 24 hours
0.37in
Last 3 days
0.96in

Visibility

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

Visibility stays 7 miles or more through Sat 7 PM, lowest 8 miles Fri 3 PM.

FriSat

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

What is measuring near here

The 7 instruments nearest Cortland, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 0.2 miles away.

measured now5 instruments

De KalbDKB

At an airfield/0.8 mi away/915 ft/17 ft above here

temp, wind, gust, visibility, precip, pressure

Rank411of 1,393

ShabbonaSBNI2

At a river or reservoir gauge/10.1 mi away/863 ft/35 ft below here

temp, wind, gust, humidity, pressure

Rank558of 1,393

measured daily2 instruments

Station report

The weather at De Kalb, drawn

The nearest airport reporting now, 0.8 mi from Cortland, Illinois. From its report of Oct 15, 2026, 10:15 PM local time: 3 of its 6 sheets.

The sky

Broken at 1,000 ft, overcast at 1,700 ft; the ceiling is 1,000 ft; visibility 7 mi.

Section of the sky over De Kalb, height above the station to scale: broken cloud with its base at 1,000 feet, overcast cloud with its base at 1,700 feet, the ceiling at 1,000 feet, and visibility of 7 mi.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT DKBFIG. A THE SKY OVER DE KALBSECTION, 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 SHEETOVC 1,700 FTOVERCAST, 8 EIGHTHS OF THE SKYBKN 1,000 FTBROKEN, 5 TO 7 EIGHTHS OF THE SKYCEILING 1,000 FTVISIBILITY, MILES: 7 MI0510TITLEDe Kalb, the skySTATION REPORT · ASOS DKBTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-DKB-1DRAWN AS linework on paperSOURCES FB-SKY-001, FB-SKY-017, FB-SKY-016, FB-SKY-018

The air

56.5 F with a dew point of 56.5 F, 100 per cent relative humidity. The air is saturated at the ground; the lowest cloud reported is at 1,000 ft.

Chart of the air at De Kalb: temperature 56.5 degrees Fahrenheit and dew point 56.5, 100 per cent relative humidity; the air saturated at the ground, against the lowest cloud reported at 1,000 feet; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT DKBFIG. B THE AIR AT DE KALBTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00050 F60 F70 FSATURATED AT THE GROUNDLOWEST CLOUD REPORTED, BKN 1,000 FTTEMPERATURE AND DEW POINT 56.5 F, 56.5 FRELATIVE HUMIDITY 100 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 POINTTITLEDe Kalb, the airSTATION REPORT · ASOS DKBTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-DKB-2DRAWN AS linework on paperSOURCES FB-WAT-020, FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the west northwest (290 degrees) at 16 mph, gusting 22 mph: force 4, a moderate breeze on the Beaufort scale. The strongest gust today was 26 mph.

Plan of the wind at De Kalb, north up: blowing from 290 degrees, the west northwest, at 16 miles an hour, gusting 22; beside it the Beaufort scale from calm to hurricane force, force 4, moderate breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT DKBFIG. C THE WIND AT DE KALBPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 290°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE13NOW, 16 MPH5FRESH BREEZE19GUST, 22 MPH6STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLEDe Kalb, the windSTATION REPORT · ASOS DKBTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-DKB-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

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

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Snow on the ground

Elsewhere in Illinois

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

Near Cortland

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

Near Cortland

River and lake gauges