Storm Station
Mark, Illinois
51° 74°/49°
Clear· Feels like 51°·Light breeze 6 mph ENE
Partly cloudy, with a low around 51. East wind around 5 mph.
0UV Low
37Air quality
93%Humidity
2%Cloud
Now
3:15 AM
51feels51
now, clear
Today
Sep 27
7449
overcast
Mon
Sep 28
7550
overcast
Tue
Sep 29
7754
overcast
Wed
Sep 30
8465
50%
13mph
overcast
Thu
Oct 1
7657
64%
14mph
showers light
Fri
Oct 2
6348
42%
13mph
overcast
Sat
Oct 3
6744
28%
overcast
51°
74°49°
75°50°
77°54°
84°65°
76°57°
63°48°
67°44°

As of 3:15 AM in Mark, Illinois.

What is measuring near here

The 4 instruments nearest Mark, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 4.7 miles away.

measured now2 instruments

PeruVYS

At an airfield/7.8 mi away/653 ft/26 ft below here

temp, wind, gust, visibility, precip, pressure

Rank376of 417

Illinois River AT Starved RockSRDI2

At a river or reservoir gauge/21.2 mi away/558 ft/121 ft below here

temp, wind, gust, humidity, pressure

Rank404of 417

measured daily2 instruments

HennepinHNPI2

At a cooperative observer's station/4.7 mi away/513 ft/166 ft below here

snowfall, snow depth, precip, high, low

Rank-

McNabb 1.4 NWIL-PM-6

In a volunteer observer's own ground/5.1 mi away/688 ft/9 ft above here

precip, snowfall, snow depth

Rank-

Station report

The weather at Peru, drawn

The nearest airport reporting now, 7.8 mi from Mark. From its report of Sep 27, 2026, 3:01 AM 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 Peru, 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 VYSFIG. A THE SKY OVER PERUSECTION, 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 MORE0510TITLEPeru, the skySTATION REPORT · ASOS VYSTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-09-27IDSR-VYS-1DRAWN AS linework on paperSOURCES FB-SKY-001

The air

50.0 F with a dew point of 48.2 F, 93 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 400 ft up.

Chart of the air at Peru: temperature 50.0 degrees Fahrenheit and dew point 48.2, 93 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 400 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT VYSFIG. B THE AIR AT PERUTHE 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 400 FT ABOVE THE STATION, AT 47.8 FTEMPERATURE AND DEW POINT 50.0 F, 48.2 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 POINTTITLEPeru, the airSTATION REPORT · ASOS VYSTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-09-27IDSR-VYS-2DRAWN AS linework on paperSOURCES FB-WAT-020, FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the northeast (40 degrees) at 5 mph: force 2, a light breeze on the Beaufort scale.

Plan of the wind at Peru, north up: blowing from 40 degrees, the northeast, at 5 miles an hour; beside it the Beaufort scale from calm to hurricane force, force 2, light breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT VYSFIG. C THE WIND AT PERUPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 40°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE4NOW, 5 MPH3GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLEPeru, the windSTATION REPORT · ASOS VYSTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-09-27IDSR-VYS-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

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

0in

Snow on the ground

Measured at Hennepin (HNPI2), 4.7 miles from here, read 26 Sep, 17:00. measured daily

Elsewhere in Illinois

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

Near Mark

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