Plan a flight · Sun 8:09 pm MDT (02:09 UTC)

Boise Air Trml/Gowen Field to Bozeman Yellowstone International BOI → BZN

254 nautical miles (292 statute miles) northeast on a straight line, true course 057°, about 044° magnetic at the departure end (variation 13E). At 120 knots that is 1 h 18 min at the quickest height in today's winds (34,000 ft, a 75-knot tailwind), arriving about 9:27 pm MDT (03:27 UTC), after sunset at the destination. Right now BOI is VFR, wind from the southeast (130°) at 9 knots; BZN is IFR, wind calm. For planning, not a briefing: the legal preflight briefing comes from Flight Service (1-800-WX-BRIEF) or the FAA's own tools. Airlines fly this pair: 361 flights in the DOT's last twelve reported months, the route's page.

The route the straight line, the warnings crossed, restrictions, pilot reports and the airports along the way · click a mark for its words

Green, blue, red and purple airport dots are the flying conditions reported there now (VFR, marginal VFR, IFR, low IFR); grey means no report. Red areas are SIGMETs, orange areas AIRMETs, hatched red areas temporary flight restrictions. Map tiles: OpenFreeMap, data © OpenStreetMap contributors.

Warnings the route crosses SIGMETs and AIRMETs whose area the line passes through or comes within 25 nm of

AIRMET ZULU 3C: moderate icing up to 22,000 ft. Over the first 156 nm of the route.
AIRMET TANGO 4W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Over the whole route.
AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the last 205 nm of the route.
AIRMET SIERRA 4E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist). Over the last 195 nm of the route.
AIRMET ZULU 2C: moderate icing up to 16,000 ft. Over the route from 166 to 176 nm out.
AIRMET TANGO 4W: moderate turbulence below 18,000 ft up to 18,000 ft. Near the route, at the destination end.

A SIGMET warns of weather hazardous to all aircraft; an AIRMET of weather that matters to small aircraft and to flying without instruments. "From 60 to 180 nm out" is measured along the route from BOI.

Pilot reports along the route within 50 nm of the line, last three hours, the serious ones first

PC12 at 6,000 ft, 48 nm southeast, 7:09 pm MDT (01:09 UTC): scattered clouds up to 6,000 ft, remarks: multiple scattered layers during the descent runway 31. 68 nm along the route, 48 nm southeast of the line.
as filed, and in English
```
SUN UA /OV KSUN/TM 0109/FL060/TP PC12/SK SCT-TOP060/WX FV05SM/RM MULTIPLE SCT LAYERS DURD RY31
```
Report
a routine report filed through SUN
Where
over KSUN
Time
01:09 UTC
Height
at 6,000 ft
Aircraft
PC12
Sky
scattered clouds, tops 6,000 ft
Weather
flight visibility 5 miles
Remarks
multiple scattered layers during the descent runway 31
E550 at 21,000 ft, 48 nm southeast, 5:27 pm MDT (23:27 UTC): light turbulence, a few clouds above 7,000 ft, remarks: during the climb zlc. 68 nm along the route, 48 nm southeast of the line.
as filed, and in English
```
SUN UA /OV SUN/TM 2327/FL210/TP E550/SK FEW070/TB CONS LGT/RM DURC /ZLC
```
Report
a routine report filed through SUN
Where
over SUN
Time
23:27 UTC
Height
at 21,000 ft
Aircraft
E550
Sky
a few clouds from 7,000 ft
Turbulence
continuous light
Remarks
during the climb zlc
B738 at 24,000 ft, 23 nm northwest, 5:13 pm MDT (23:13 UTC): remarks: snow top flight level at 24,000 ft zlc. 234 nm along the route, 23 nm northwest of the line.
as filed, and in English
```
BZN UA /OV BZN270030/TM 2313/FL240/TP B738/RM SN TOP FL 240 /ZLC
```
Report
a routine report filed through BZN
Where
30 nm west (270°) of BZN
Time
23:13 UTC
Height
at 24,000 ft
Aircraft
B738
Remarks
snow top flight level at 24,000 ft zlc
E75L descending, 0 nm northwest, 7:04 pm MDT (01:04 UTC): remarks: had the airport in sight at 400-500FT above ground. At the destination end, 0 nm northwest of the line.
as filed, and in English
```
BZN UA /OV BZN/TM 0104/FLDURD/TP E75L/RM HAD THE AIRPORT IN SIGHT AT 400-500FT AGL
```
Report
a routine report filed through BZN
Where
over BZN
Time
01:04 UTC
Height
during the descent
Aircraft
E75L
Remarks
had the airport in sight at 400-500FT above ground
B737 descending, 0 nm northwest, 6:28 pm MDT (00:28 UTC): scattered clouds above 8,000 ft, fog, snow, remarks: broke out about 100FT above mins. At the destination end, 0 nm northwest of the line.
as filed, and in English
```
BZN UA /OV BZN/TM 0028/FLDURD/TP B737/SK SCT080/WX 1/2SM SN FG/RM BROKE OUT ABOUT 100FT ABOVE MINS
```
Report
a routine report filed through BZN
Where
over BZN
Time
00:28 UTC
Height
during the descent
Aircraft
B737
Sky
scattered clouds from 8,000 ft
Weather
1/2SM, snow, fog
Remarks
broke out about 100FT above mins

Winds aloft along the route, and the time en route the forecast for use 20:00–03:00 UTC · at 120 knots true airspeed

The eastbound cruising heights for this course (VFR: odd thousands plus 500 ft; above 18,000 ft the forecast levels), with the wind averaged along the line from the 2 forecast points nearest it (BOI, DLN). A plus sign is a headwind, a minus sign a tailwind.

Height	Average wind	Head- or tailwind	Temperature	Ground speed	Time en route	Arrival
7,500 ft	060° at 5 kt	+5 kt	-1 °C	115 kt	2 h 13 min	10:22 pm MDT (04:22 UTC)
9,500 ft	120° at 4 kt	+2 kt	-3 °C	118 kt	2 h 09 min	10:18 pm MDT (04:18 UTC)
11,500 ft	200° at 10 kt	−8 kt	-4 °C	128 kt	1 h 59 min	10:08 pm MDT (04:08 UTC)
13,500 ft	200° at 16 kt	−12 kt	-8 °C	132 kt	1 h 55 min	10:04 pm MDT (04:04 UTC)
15,500 ft	200° at 21 kt	−16 kt	-11 °C	136 kt	1 h 52 min	10:01 pm MDT (04:01 UTC)
17,500 ft	200° at 26 kt	−19 kt	-15 °C	139 kt	1 h 50 min	9:59 pm MDT (03:59 UTC)
18,000 ft FL180	200° at 27 kt	−20 kt	-16 °C	140 kt	1 h 49 min	9:58 pm MDT (03:58 UTC)
24,000 ft FL240	200° at 58 kt	−46 kt	-24 °C	166 kt	1 h 32 min	9:41 pm MDT (03:41 UTC)
30,000 ft FL300	200° at 75 kt	−59 kt	-35 °C	179 kt	1 h 25 min	9:34 pm MDT (03:34 UTC)
34,000 ft FL340	220° at 80 kt	−75 kt	-39 °C	195 kt	1 h 18 min	9:27 pm MDT (03:27 UTC)
39,000 ft FL390	230° at 73 kt	−72 kt	-43 °C	192 kt	1 h 19 min	9:28 pm MDT (03:28 UTC)

Based on data from the 11th at 18:00 UTC; valid on the 12th at 00:00 UTC for use 20:00 to 03:00 UTC; temperatures above 24,000 ft are below zero. Heights are above sea level; a height is left out when the forecast has no wind for it over most of the line (the ground is higher). Ground speed is the airspeed less the headwind; the time en route is for the straight line and ignores climb, descent and routing around weather.

The forecast points as issued

Point	From	3,000	6,000	9,000	12,000	18,000	24,000	30,000	34,000	39,000
BOI	used from 0 nm out; 24 nm from the line		330/14 4°	230/5 -2°	220/20 -7°	210/37 -20°	200/59 -26°	200/67 -34°	210/73 -35°	220/62 -41°
DLN	used from 98 nm out; 65 nm from the line			080/10 -3°	180/8 -3°	180/23 -14°	200/58 -22°	200/80 -36°	220/85 -41°	230/81 -45°

The weather now: both ends and the airports along the way public airports with a weather report within 25 nm of the line, one for each stretch

Airport	Where	Conditions	Wind	Visibility	Ceiling	Elevation	Reported
BOI Boise, ID	departure	VFR Sky: a broken layer at 7,500 feet, overcast at 12,000 feet	from the southeast (130°) at 9 knots	10+ mi	7,500 ft	2,871 ft	7:53 pm MDT (01:53 UTC)
LLJ Challis, ID	107 nm out, 4 nm west of the line	marginal VFR Sky: scattered clouds at 1,900 feet, overcast at 2,800 feet Weather: light rain	from the north-northwest (340°) at 9 knots	10+ mi	2,800 ft	5,075 ft	01:55 UTC
DLN Dillon, MT	186 nm out, 3 nm north of the line	low IFR Sky: a broken layer at 300 feet, overcast at 800 feet Weather: light snow, mist	from the north-northeast (030°) at 4 knots	1 mi	300 ft	5,244 ft	02:06 UTC
EKS Ennis, MT	225 nm out, 16 nm south of the line	low IFR Sky: overcast at 400 feet Weather: light snow, mist	from the north (350°) at 16 knots	1.25 mi	400 ft	5,432 ft	01:55 UTC
BZN Bozeman, MT	destination	IFR Sky: a few clouds at 600 feet, overcast at 1,500 feet Weather: light snow, mist	calm	1.25 mi	1,500 ft	4,473 ft	8:03 pm MDT (02:03 UTC)

The highest airport on this list sits at 5,432 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.

At BZN when you get there the forecast at the estimated arrival, 9:27 pm MDT (03:27 UTC)

Wind light and variable, visibility ½ mile, snow, fog, overcast at 300 feet low IFR

At times between Sun 9:00 pm MDT (03:00 UTC) and 12:00 am MDT (06:00 UTC): visibility 2 miles, light snow, mist, scattered clouds at 300 feet, overcast at 1,200 feet IFR

The whole forecast for BZN

From Sun 6:00 pm MDT (00:00 UTC): wind light and variable, visibility ½ mile, snow, fog, overcast at 300 feet
At times between Sun 9:00 pm MDT (03:00 UTC) and 12:00 am MDT (06:00 UTC): visibility 2 miles, light snow, mist, scattered clouds at 300 feet, overcast at 1,200 feet
From Mon 12:00 am MDT (06:00 UTC): wind from the west at 7 knots, visibility 2 miles, light snow, mist, overcast at 800 feet
At times between Mon 12:00 am MDT (06:00 UTC) and 3:00 am MDT (09:00 UTC): visibility 6 miles, light snow, mist, overcast at 800 feet
From Mon 3:00 am MDT (09:00 UTC): wind light and variable, visibility more than 6 miles, overcast at 800 feet
From Mon 12:00 pm MDT (18:00 UTC): wind light and variable, visibility more than 6 miles, scattered clouds at 800 feet, overcast at 2,000 feet
From Mon 5:00 pm MDT (23:00 UTC): wind light and variable, visibility more than 6 miles, scattered clouds at 1,500 feet, a broken layer at 11,000 feet

The forecast for BOI, the departure

From Sun 7:00 pm MDT (01:00 UTC): wind from the northwest at 11 knots, visibility more than 6 miles, showers nearby, scattered clouds at 5,000 feet, overcast at 7,000 feet
At times between Sun 7:00 pm MDT (01:00 UTC) and 10:00 pm MDT (04:00 UTC): wind variable at 10 knots, light rain showers, overcast at 5,000 feet
From Mon 12:00 am MDT (06:00 UTC): wind from the west-northwest at 5 knots, visibility more than 6 miles, a few clouds at 5,000 feet, a broken layer at 8,000 feet
From Mon 12:00 pm MDT (18:00 UTC): wind from the northwest at 10 knots, visibility more than 6 miles, a broken layer at 10,000 feet

Temporary flight restrictions on the line or within 25 nm of it

No temporary flight restriction on or near this route right now.

Daylight

Sunset at BOI 7:06 pm MDT (01:06 UTC), at BZN 6:44 pm MDT (00:44 UTC) (civil twilight ends 7:14 pm MDT (01:14 UTC)). At 120 knots the arrival at BZN is after sunset there (6:46 pm MDT (00:46 UTC)).

Each restriction opens the FAA's own page with the exact area, heights and times. Ordinary notices to air missions (closed runways, lights out) are not shown: the FAA's notice search is not open to sites like this one at this time.

Radar and forecast charts for the regions crossed government pictures, the latest each time the page loads

Radar now, the Pacific Northwest · loop National Weather Service

Radar now, the northern Rockies · loop National Weather Service

Radar, the whole country · loop National Weather Service

Surface analysis now Weather Prediction Center

Forecast chart, 12 hours ahead Weather Prediction Center

Forecast chart, 24 hours ahead Weather Prediction Center

Sources: the Aviation Weather Center's data service (SIGMETs, AIRMETs, graphical AIRMETs, pilot reports, winds and temperatures aloft, observations and terminal forecasts), the National Weather Service radar, the Weather Prediction Center's charts, the FAA's temporary flight restriction list and shapes, and the FAA's airport file for the positions, elevations and magnetic variation. Fetched when the page is viewed and kept a few minutes. Each leg is the straight line between its two airports; airways, terrain and airspace are not considered. The airports in detail: Boise Air Trml/Gowen Field, Bozeman Yellowstone International.