Storm Station
Sign in

Roy, Montana

Community in Fergus County, Montana

Air quality

The air at Roy

Index 28, good, led by ozone. Read at 10 PM from its reporting area, Lewistown (MT), 30 miles off.

28Good
  • Fine particles (PM2.5)24Good-
  • Ozone28Good-
  • Coarse particles (PM10)6Good-

The days ahead

Yesterday measured 35, good.

Smoke, the next 44 hours

Little smoke near the ground through Sat 6 PM: the index from smoke stays at 6 or under.

FriSat

Precipitation

What has fallen at Roy

None in the last 3 days, to Thu 10 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 Roy, the next 44 hours

Visibility stays 10 miles or more through Sat 6 PM.

FriSat

On the radar over Roy, MontanaReflectivityStorm topsRain rateRain, last 24 hoursForecast temperatureForecast rain totalEvery picture

What is measuring near here

The 5 instruments nearest Roy, how far away each one is, how high it stands, and what kind of measurement it makes. The nearest is 7.3 miles away.

measured now3 instruments

Judith RAWSJPKM8

A remote fire weather station/14.8 mi away/6,351 ft/2,863 ft above here

temp, wind, gust, humidity, pressure

Rank666of 1,053

Lewistown MunicipalLWT

At an airfield/30.9 mi away/4,167 ft/679 ft above here

temp, wind, gust, visibility, precip, pressure

Rank-

measured daily2 instruments

ValentineVALM8

At a cooperative observer's station/21.5 mi away/2,910 ft/578 ft below here

snowfall, snow depth, precip, high, low

Rank578of 1,053

Lewistown 0.4 SWMT-FG-6

In a volunteer observer's own ground/29.3 mi away/4,019 ft/531 ft above here

precip, snowfall, snow depth

Rank-

Station report

The weather at Bohemian Corner JCT MT-19/US-191 MT US MT DOT, drawn

The nearest instrument reporting now, 7.3 mi from Roy, Montana. From its report of Oct 15, 2026, 10:15 PM local time: 3 of its 5 sheets.

The air

30.0 F with a dew point of 25.8 F, 84 per cent relative humidity. Air lifted from the station would cool to its dew point, where cloud forms, about 1,000 ft up.

Chart of the air at Bohemian Corner JCT MT-19/US-191 MT US MT DOT: temperature 30.0 degrees Fahrenheit and dew point 25.8, 84 per cent relative humidity; air lifted from the station cools along the dry rate and meets its dew point about 1,000 feet above the station; height to scale.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT MTBOHFIG. B THE AIR AT BOHEMIAN CORNER JCT MT-19/US-191 MT US MT DOTTHE REPORTED TEMPERATURE AND DEW POINT, AND AIR LIFTED FROM THE STATION WITHOUT MIXING UNTIL IT SATURATES; HEIGHT ABOVE THE STATION TO SCALEFT ABOVE THE STATION01,0002,0003,00010 F20 F30 F40 FSATURATES 1,000 FT ABOVE THE STATION, AT 24.9 FTEMPERATURE 30.0 FDEW POINT 25.8 FSPREAD 4.2 FRELATIVE HUMIDITY 84 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 POINTTITLEBohemian Corner JCT MT-19/US-191 MT US MT DOT, the airSTATION REPORT · RWIS MTBOHTYPECHARTSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 1 of 5DATE2026-10-16IDSR-MTBOH-1DRAWN AS linework on paperSOURCES FB-WAT-002, FB-ENG-011, FB-ENG-005

The wind

From the south (180 degrees) at 2 mph, gusting 5 mph: force 1, a light air on the Beaufort scale. The strongest gust today was 37 mph.

Plan of the wind at Bohemian Corner JCT MT-19/US-191 MT US MT DOT, north up: blowing from 180 degrees, the south, at 2 miles an hour, gusting 5; beside it the Beaufort scale from calm to hurricane force, force 1, light air, marked.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT MTBOHFIG. C THE WIND AT BOHEMIAN CORNER JCT MT-19/US-191 MT US MT DOTPLAN, NORTH UP: THE WIND AS REPORTED, AND WHERE IT SITS ON THE BEAUFORT SCALENESWTHE STATIONFROM 180°BEAUFORT FORCELEAST WIND, MPH0CALM01LIGHT AIR1NOW, 2 MPH2LIGHT BREEZE4GUST, 5 MPH3GENTLE BREEZE84MODERATE BREEZE135FRESH BREEZE196STRONG BREEZE257NEAR GALE328GALE399STRONG GALE4710STORM5511VIOLENT STORM6412HURRICANE FORCE73TITLEBohemian Corner JCT MT-19/US-191 MT US MT DOT, the windSTATION REPORT · RWIS MTBOHTYPEPLAN north upSCALENOT TO SCALEREVAS REPORTED SHEET 2 of 5DATE2026-10-16IDSR-MTBOH-2DRAWN AS linework on paperSOURCES FB-EVT-150, FB-ENG-008

The column

At 3,284 ft above sea level, 11 per cent of the atmosphere's air lies below the station. The standard atmosphere puts the pressure there at 26.54 inHg and the temperature at 47.3 F; it reports 30.0 F, 17.3 F colder than standard.

Section from sea level of where Bohemian Corner JCT MT-19/US-191 MT US MT DOT stands in the atmosphere, height to scale: the station 3,284 feet above sea level with 11 per cent of the air below it; the standard atmosphere's pressure there, 26.54 inches of mercury, and temperature, 47.3 degrees Fahrenheit.1122334455667788AABBCCDDEE© 2026 STORM STATION 247THE FIELD BOOKSTATION REPORT MTBOHFIG. D WHERE BOHEMIAN CORNER JCT MT-19/US-191 MT US MT DOT STANDS IN THE ATMOSPHERESECTION FROM SEA LEVEL, HEIGHT TO SCALE, THE STATION IN THE STANDARD ATMOSPHEREFT ABOVE SEA LEVEL05,00010,00015,000SEA LEVEL, 29.92 inHg IN THE STANDARD ATMOSPHEREBOHEMIAN CORNER JCT MT-19/US-191 MT US MT DOT11 PER CENT OF THE AIR BELOW IT3,284 FT10 PER CENT OF THE AIR BELOW, 2,890 FT20 PER CENT OF THE AIR BELOW, 6,050 FT30 PER CENT OF THE AIR BELOW, 9,540 FT40 PER CENT OF THE AIR BELOW, 13,470 FTSTANDARD PRESSURE HERE26.54 inHgSTANDARD TEMPERATURE HERE47.3 FTEMPERATURE, REPORTED30.0 FTITLEBohemian Corner JCT MT-19/US-191 MT US MT DOT, the columnSTATION REPORT · RWIS MTBOHTYPESECTIONSCALEHEIGHT TO SCALEREVAS REPORTED SHEET 3 of 5DATE2026-10-16IDSR-MTBOH-3DRAWN AS linework on paperSOURCES FB-ENG-001, FB-ENG-003

The full report of Bohemian Corner JCT MT-19/US-191 MT US MT DOT, in 5 sheets, each beside the Field Book plates that explain it

0in

Snow on the ground

Measured at Valentine (VALM8), 21.5 miles from here, read 15 Oct, 07:00. measured daily

Elsewhere in Montana

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

Near Roy

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

Near Roy

River and lake gauges