Plan a flight · Sun 7:33 pm MDT (01:33 UTC)

Jackson Hole Airport to Boeing Fld/King County International JAC → BFI

539 nautical miles (621 statute miles) northwest on a straight line, true course 300°, about 287° magnetic at the departure end (variation 13E). At 120 knots that is 4 h 17 min at the quickest height in today's winds (16,500 ft, a 6-knot tailwind), arriving about 10:50 pm PDT (05:50 UTC), after sunset at the destination. Right now JAC is marginal VFR, wind from the west-northwest (290°) at 5 knots; BFI is VFR, wind from the northwest (310°) at 6 knots. 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: 1 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 SIERRA 4E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist), from 6:00 pm MDT (00:00 UTC). Over the first 210 nm of the route.
AIRMET TANGO 1W: low-level wind shear (due to air speed loss or gain of 20 knots or more below 2,000 ft above the ground), from 6:00 pm MDT (00:00 UTC). Over the first 20 nm of the route.
AIRMET ZULU 3C: moderate icing up to 22,000 ft, from 6:00 pm MDT (00:00 UTC). Over the first 110 nm of the route.
AIRMET TANGO 4W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft, from 6:00 pm MDT (00:00 UTC). Over the first 280 nm of the route.
AIRMET TANGO 4W: moderate turbulence below 18,000 ft up to 18,000 ft, from 6:00 pm MDT (00:00 UTC). Over the first 40 nm of the route.
AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist), from 6:00 pm MDT (00:00 UTC). Over the first 360 nm of the route.
AIRMET ZULU 2C: moderate icing up to 14,000 ft, from 6:00 pm MDT (00:00 UTC). Over the route from 220 to 420 nm out.
AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 25,000 ft to 39,000 ft, from 6:00 pm MDT (00:00 UTC). Over the last 0 nm of the route.

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 JAC.

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

B738 at 33,000 ft, 24 nm northeast, 5:57 pm MDT (23:57 UTC): moderate chop turbulence from 31,000 ft to 33,000 ft. 70 nm along the route, 24 nm northeast of the line.
as filed, and in English
```
IDA UA /OV DBS015030/TM 2357/FL330/TP B738/TB MOD CHOP 310-330 /ZLC
```
Report
a routine report filed through IDA
Where
30 nm north (015°) of DBS
Time
23:57 UTC
Height
at 33,000 ft
Aircraft
B738
Turbulence
moderate chop from 31,000 ft to 33,000 ft zlc
A320 descending, 1 nm north, 6:54 pm MDT (00:54 UTC): overcast above 7,500 ft, remarks: braking action good during the descent RY19. At the departure end, 1 nm north of the line.
as filed, and in English
```
JAC UA /OV JAC/TM 0054/FLUNKN/TP A320/SK OVC075/RM BRAKING ACTION GOOD DURD RY19
```
Report
a routine report filed through JAC
Where
over JAC
Time
00:54 UTC
Height
height not given
Aircraft
A320
Sky
overcast from 7,500 ft
Remarks
braking action good during the descent RY19
PC12 at 15,000 ft, 24 nm southwest, 5:47 pm MDT (23:47 UTC): light rime icing above 15,000 ft. At the departure end, 24 nm southwest of the line.
as filed, and in English
```
JAC UA /OV JAC200025/TM 2347/FL150/TP PC12/IC LGT RIME 150 /ZLC
```
Report
a routine report filed through JAC
Where
25 nm south (200°) of JAC
Time
23:47 UTC
Height
at 15,000 ft
Aircraft
PC12
Icing
light rime at 15,000 ft zlc
CRJ7 at 17,000 ft, 29 nm south, 5:03 pm MDT (23:03 UTC): light rime icing, -6 °C. At the departure end, 29 nm south of the line.
as filed, and in English
```
JAC UA /OV JAC160030/TM 2303/FL170/TP CRJ7/TA M6/IC LGT RIME /ZLC
```
Report
a routine report filed through JAC
Where
30 nm south (160°) of JAC
Time
23:03 UTC
Height
at 17,000 ft
Aircraft
CRJ7
Temperature
−6 °C
Icing
light rime zlc
PC12 at 6,000 ft, 30 nm south, 6:56 pm MDT (00:56 UTC): overcast above 6,000 ft. 360 nm along the route, 30 nm south of the line.
as filed, and in English
```
ALW UA /OV ALW200015/TM 0056/FL060/TP PC12/SK OVC060
```
Report
a routine report filed through ALW
Where
15 nm south (200°) of ALW
Time
00:56 UTC
Height
at 6,000 ft
Aircraft
PC12
Sky
overcast from 6,000 ft
PC12 at 13,500 ft, 7 nm north, 7:08 pm MDT (01:08 UTC): no turbulence, a trace of icing, overcast from 9,000 ft to 13,500 ft, -10 °C. 390 nm along the route, 7 nm north of the line.
as filed, and in English
```
PSC UA /OV PSC360025/TM 0108/FL135/TP PC12/SK OVC090-TOP135/TA M10/TB NEG /IC TRACE RM 135-090
```
Report
a routine report filed through PSC
Where
25 nm north (360°) of PSC
Time
01:08 UTC
Height
at 13,500 ft
Aircraft
PC12
Sky
overcast from 9,000 ft, tops 13,500 ft
Temperature
−10 °C
Turbulence
none
Icing
trace remarks from 13,500 ft to 9,000 ft
C337 at 12,000 ft, 42 nm south, 7:18 pm MDT (01:18 UTC): light rime icing, -12 °C, remarks: zse. 439 nm along the route, 42 nm south of the line.
as filed, and in English
```
YKM UA /OV YKM155020/TM 0118/FL120/TP C337/TA M12/IC LGT RIME/RM ZSE
```
Report
a routine report filed through YKM
Where
20 nm southeast (155°) of YKM
Time
01:18 UTC
Height
at 12,000 ft
Aircraft
C337
Temperature
−12 °C
Icing
light rime
Remarks
zse
PC12 at 13,000 ft, 26 nm south, 6:42 pm MDT (00:42 UTC): remarks: zse. 499 nm along the route, 26 nm south of the line.
as filed, and in English
```
YKM UA /OV YKM270050/TM 0042/FL130/TP PC12/SK TOP130/RM -ZSE
```
Report
a routine report filed through YKM
Where
50 nm west (270°) of YKM
Time
00:42 UTC
Height
at 13,000 ft
Aircraft
PC12
Sky
TOP130
Remarks
zse
PC12 at 15,000 ft, 26 nm south, 6:42 pm MDT (00:42 UTC): remarks: zse. 499 nm along the route, 26 nm south of the line.
as filed, and in English
```
YKM UA /OV YKM270050/TM 0042/FL150/TP PC12/SK TOP130/RM -ZSE
```
Report
a routine report filed through YKM
Where
50 nm west (270°) of YKM
Time
00:42 UTC
Height
at 15,000 ft
Aircraft
PC12
Sky
TOP130
Remarks
zse

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 westbound cruising heights for this course (VFR: even thousands plus 500 ft; above 18,000 ft the forecast levels), with the wind averaged along the line from the 5 forecast points nearest it (PIH, DLN, LWS, YKM, SEA). A plus sign is a headwind, a minus sign a tailwind.

Height	Average wind	Head- or tailwind	Temperature	Ground speed	Time en route	Arrival
4,500 ft	020° at 9 kt	0		120 kt	4 h 30 min	11:03 pm PDT (06:03 UTC)
6,500 ft	030° at 12 kt	−1 kt	-2 °C	121 kt	4 h 27 min	11:00 pm PDT (06:00 UTC)
8,500 ft	040° at 12 kt	−3 kt	-5 °C	123 kt	4 h 23 min	10:56 pm PDT (05:56 UTC)
10,500 ft	050° at 7 kt	−3 kt	-6 °C	123 kt	4 h 23 min	10:56 pm PDT (05:56 UTC)
12,500 ft	120° at 3 kt	−4 kt	-9 °C	124 kt	4 h 21 min	10:54 pm PDT (05:54 UTC)
14,500 ft	160° at 6 kt	−5 kt	-13 °C	125 kt	4 h 19 min	10:52 pm PDT (05:52 UTC)
16,500 ft	170° at 9 kt	−6 kt	-16 °C	126 kt	4 h 17 min	10:50 pm PDT (05:50 UTC)
18,000 ft FL180	180° at 11 kt	−6 kt	-19 °C	126 kt	4 h 17 min	10:50 pm PDT (05:50 UTC)
24,000 ft FL240	210° at 22 kt	−1 kt	-26 °C	121 kt	4 h 27 min	11:00 pm PDT (06:00 UTC)
30,000 ft FL300	210° at 30 kt	−1 kt	-36 °C	121 kt	4 h 27 min	11:00 pm PDT (06:00 UTC)
34,000 ft FL340	230° at 37 kt	+10 kt	-38 °C	110 kt	4 h 54 min	11:27 pm PDT (06:27 UTC)
39,000 ft FL390	240° at 39 kt	+19 kt	-42 °C	101 kt	5 h 20 min	11:53 pm PDT (06:53 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
PIH	used from 0 nm out; 80 nm from the line		270/10	270/13 1°	210/16 -2°	200/56 -11°	200/51 -23°	200/68 -33°	220/77 -37°	230/73 -44°
DLN	used from 50 nm out; 64 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°
LWS	used from 200 nm out; 91 nm from the line	010/5	050/14 -2°	040/12 -6°	160/7 -10°	190/30 -22°	200/54 -27°	200/48 -35°	210/40 -37°	230/32 -41°
YKM	used from 400 nm out; 37 nm from the line	030/16	020/18 0°	030/30 -8°	030/23 -13°	020/40 -23°	010/73 -29°	010/54 -36°	360/29 -37°	330/16 -40°
SEA	used from 499 nm out; 19 nm from the line	360/9	350/10 1°	010/10 -5°	030/20 -11°	020/60 -17°	010/86 -26°	360/90 -40°	010/68 -42°	360/31 -43°

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
JAC Jackson, WY	departure	marginal VFR Sky: a few clouds at 500 feet, a broken layer at 1,100 feet, overcast at 3,500 feet Weather: heavy rain, mist	from the west-northwest (290°) at 5 knots	3 mi	1,100 ft	6,451 ft	6:56 pm MDT (00:56 UTC)
DIJ Driggs, ID	20 nm out, 3 nm southeast of the line	IFR Sky: a broken layer at 500 feet, a broken layer at 900 feet, overcast at 1,800 feet Weather: light rain	from the west (260°) at 3 knots	10+ mi	500 ft	6,257 ft	00:56 UTC
SMN Salmon, ID	160 nm out, 15 nm north of the line	VFR Sky: a few clouds at 1,600 feet, overcast at 3,200 feet Weather: light rain	from the north (350°) at 9 knots, gusting to 15	10+ mi	3,200 ft	4,044 ft	00:56 UTC
LWS Lewiston, ID	310 nm out, 23 nm north of the line, tower	VFR Sky: overcast at 6,000 feet	from the west (270°) at 6 knots	10+ mi	6,000 ft	1,442 ft	00:56 UTC
ALW Walla Walla, WA	350 nm out, 15 nm southwest of the line, tower	VFR Sky: overcast at 5,000 feet	from the south-southwest (210°) at 3 knots	10+ mi	5,000 ft	1,194 ft	00:53 UTC
PSC Pasco, WA	390 nm out, 19 nm southwest of the line, tower	VFR Sky: overcast at 9,500 feet	from the northeast (040°) at 11 knots	10+ mi	9,500 ft	410 ft	00:53 UTC
ELN Ellensburg, WA	459 nm out, 2 nm west of the line	VFR Sky: overcast at 9,000 feet	from the north-northeast (020°) at 4 knots	10+ mi	9,000 ft	1,763 ft	00:53 UTC
ESW Easton, WA	489 nm out, 2 nm north of the line	no report just now				2,226 ft
BFI Seattle, WA	destination	VFR	from the northwest (310°) at 6 knots	10+ mi	none	21 ft	5:53 pm PDT (00:53 UTC)

The highest airport on this list sits at 6,451 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.

At BFI when you get there the forecast at the estimated arrival, 10:50 pm PDT (05:50 UTC)

Wind light and variable, visibility more than 6 miles, clear skies VFR

The whole forecast for BFI

From Sun 5:00 pm PDT (00:00 UTC): wind from the north-northwest at 8 knots, gusting to 18, visibility more than 6 miles, a few clouds at 5,000 feet
From Sun 7:00 pm PDT (02:00 UTC): wind light and variable, visibility more than 6 miles, clear skies
From Mon 3:00 am PDT (10:00 UTC): wind light and variable, visibility more than 6 miles, patches of fog, clear skies
From Mon 9:00 am PDT (16:00 UTC): wind from the south-southeast at 3 knots, visibility more than 6 miles, clear skies
From Mon 12:00 pm PDT (19:00 UTC): wind from the west-southwest at 3 knots, visibility more than 6 miles, clear skies
From Mon 2:00 pm PDT (21:00 UTC): wind from the west at 5 knots, visibility more than 6 miles, clear skies

The forecast for JAC, the departure

From Sun 6:00 pm MDT (00:00 UTC): wind from the west at 7 knots, visibility 6 miles, light rain showers, scattered clouds at 700 feet, a broken layer at 1,200 feet and more above
At times between Sun 6:00 pm MDT (00:00 UTC) and 9:00 pm MDT (03:00 UTC): visibility 3 miles, rain, a broken layer at 700 feet
From Sun 9:00 pm MDT (03:00 UTC): wind from the north-northeast at 5 knots, visibility more than 6 miles, showers nearby, scattered clouds at 1,500 feet, overcast at 2,500 feet
From Mon 7:00 am MDT (13:00 UTC): wind from the north-northeast at 5 knots, visibility 6 miles, light rain showers, scattered clouds at 1,000 feet, overcast at 1,800 feet
From Mon 3:00 pm MDT (21:00 UTC): wind from the southwest at 4 knots, visibility more than 6 miles, scattered clouds at 2,500 feet, overcast at 5,000 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 JAC 6:44 pm MDT (00:44 UTC), at BFI 6:27 pm PDT (01:27 UTC) (civil twilight ends 6:58 pm PDT (01:58 UTC)). At 120 knots the arrival at BFI is after sunset there (6:29 pm PDT (01:29 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 northern Rockies · loop National Weather Service

Radar now, the Pacific Northwest · 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: Jackson Hole Airport, Boeing Fld/King County International.