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Defiance, Missouri

Community in St. Charles County, Missouri

Air quality

The air at Defiance

Index 23, good, led by fine particles. Read at 7 AM from its reporting area, Saint Louis (MO), 4 miles off.

23Good
  • Fine particles (PM2.5)23Good24.1 mi
  • Ozone21Good19 ppb10.5 mi
  • Coarse particles (PM10)21Good24.1 mi
  • Nitrogen dioxide1Good1.6 ppb19.8 mi
  • Sulfur dioxide0Good0.2 ppb19.8 mi

The days ahead

Yesterday measured 40, good.

Smoke, the next 43 hours

No smoke near the ground through Sun 1 AM.

FriSat

Precipitation

What has fallen at Defiance

0.35 in in the last 24 hours, 0.97 in over the last 3 days, to Fri 6 AM. Measured by radar and rain gauges, as water.

Last 24 hours
0.35in
Last 3 days
0.97in

Visibility

How far you can see at Defiance, the next 43 hours

Visibility stays 9 miles or more through Sun 1 AM, lowest 10 miles Fri 8 PM.

FriSat

On the radar over Defiance, MissouriReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 6 instruments nearest Defiance, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 3.9 miles away.

measured now4 instruments

measured daily2 instruments

Wildwood 3.0 NNEMO-SL-21

In a volunteer observer's own ground/5.8 mi away/590 ft/54 ft above here

precip, snowfall, snow depth

Rank-

St Louis NWSLSX

At a cooperative observer's station/7.0 mi away/610 ft/74 ft above here

snowfall, snow depth, precip, high, low

Rank242of 1,014

Station report

The weather at St. Louis/Spirit, drawn

The nearest airport reporting now, 7.1 mi from Defiance, Missouri. From its report of Oct 16, 2026, 6:54 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 St. Louis/Spirit, 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 SUSFIG. A THE SKY OVER ST. LOUIS/SPIRITSECTION, 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 MORE0510TITLESt. Louis/Spirit, the skySTATION REPORT · ASOS SUSTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 6DATE2026-10-16IDSR-SUS-1DRAWN AS linework on paperSOURCES FB-SKY-001

The air

50.0 F with a dew point of 41.0 F, 71 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 2,100 ft up.

Chart of the air at St. Louis/Spirit: temperature 50.0 degrees Fahrenheit and dew point 41.0, 71 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 2,100 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT SUSFIG. B THE AIR AT ST. LOUIS/SPIRITTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00030 F40 F50 F60 FSATURATES 2,100 FT ABOVE THE STATION, AT 39.0 FTEMPERATURE 50.0 FDEW POINT 41.0 FSPREAD 9.0 FRELATIVE HUMIDITY 71 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 POINTTITLESt. Louis/Spirit, the airSTATION REPORT · ASOS SUSTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 2 of 6DATE2026-10-16IDSR-SUS-2DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the west northwest (300 degrees) at 15 mph, gusting 21 mph: force 4, a moderate breeze on the Beaufort scale. The strongest gust today was 26 mph.

Plan of the wind at St. Louis/Spirit, north up: blowing from 300 degrees, the west northwest, at 15 miles an hour, gusting 21; beside it the Beaufort scale from calm to hurricane force, force 4, moderate breeze, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT SUSFIG. C THE WIND AT ST. LOUIS/SPIRITPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 300°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR12LIGHT BREEZE43GENTLE BREEZE84MODERATE BREEZE13NOW, 15 MPH5FRESH BREEZE19GUST, 21 MPH6STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLESt. Louis/Spirit, the windSTATION REPORT · ASOS SUSTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 3 of 6DATE2026-10-16IDSR-SUS-3DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008, FB-INS-002

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

0in

Snow on the ground

Measured at St Louis NWS (LSX), 7.0 miles from here, read 16 Oct, 06:00. measured daily

Elsewhere in Missouri

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

Near Defiance

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

Near Defiance

River and lake gauges