Plan a flight · Sun 8:35 pm PDT (03:35 UTC)

Boeing Fld/King County International to San Antonio International BFI → SAT

1,544 nautical miles (1,777 statute miles) southeast on a straight line, true course 126°, about 111° magnetic at the departure end (variation 15E). At 120 knots that is 11 h 47 min at the quickest height in today's winds (34,000 ft, a 11-knot tailwind), arriving about 10:22 am CDT (15:22 UTC). Right now BFI is VFR, wind calm; SAT is VFR, wind from the southeast (140°) at 12 knots, gusting to 20. 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: 3 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

SIGMET W11W: thunderstorms (a convective SIGMET) up to 34,000 ft, moving from the southwest at 40 knots, until 9:55 pm PDT (04:55 UTC). Over the route from 847 to 1006 nm out.
as issued
```
WSUS33 KKCI 120255
MKCW WST 120255
CONVECTIVE SIGMET 11W
VALID UNTIL 0455Z
CO NM
FROM 20WNW PUB-10ENE CIM-50WNW ABQ-30NNE DVC-20WNW PUB
AREA TS MOV FROM 22040KT. TOPS TO FL340.
```
SIGMET 3C: thunderstorms (a convective SIGMET) up to 30,000 ft, moving from the southwest at 30 knots, until 9:55 pm PDT (04:55 UTC). Over the route from 1056 to 1086 nm out.
as issued
```
WSUS32 KKCI 120255
MKCC WST 120255
CONVECTIVE SIGMET 3C
VALID UNTIL 0455Z
TX NM
FROM 50SE CIM-70WNW MRF-30W ELP-10W FTI-50SE CIM
AREA TS MOV FROM 22030KT. TOPS TO FL300.
```
AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 39,000 ft. Over the first 179 nm of the route.
AIRMET ZULU 2C: moderate icing up to 20,000 ft. Over the route from 70 to 319 nm out.
AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the route from 199 to 767 nm out.
AIRMET ZULU 2C: moderate icing up to 23,000 ft. Over the route from 329 to 777 nm out.
AIRMET SIERRA 4E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist). Near the route, 388 nm along the route.
AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Near the route, 408 nm along the route.
AIRMET TANGO 4W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Over the route from 578 to 896 nm out.
AIRMET TANGO 4W: moderate turbulence below 18,000 ft up to 18,000 ft. Over the route from 598 to 1106 nm out.
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). Over the route from 677 to 946 nm out.
AIRMET TANGO 2W: moderate turbulence above 18,000 ft from 35,000 ft to 45,000 ft. Over the route from 906 to 1086 nm out.
AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Near the route, 936 nm along 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 BFI.

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

E75L at 22,000 ft, 35 nm southwest, 6:04 pm PDT (01:04 UTC): moderate turbulence. 667 nm along the route, 35 nm southwest of the line.
as filed, and in English
```
PUC UA /OV PUC320020/TM 0104/FL220/TP E75L/TB MOD /ZLC
```
Report
a routine report filed through PUC
Where
20 nm northwest (320°) of PUC
Time
01:04 UTC
Height
at 22,000 ft
Aircraft
E75L
Turbulence
moderate zlc
S22T at 14,000 ft, 29 nm southwest, 6:23 pm PDT (01:23 UTC): moderate rime icing, -16 °C. 677 nm along the route, 29 nm southwest of the line.
as filed, and in English
```
PUC UA /OV PUC360015/TM 0123/FL140/TP S22T/TA M16/IC MOD RIME /ZLC
```
Report
a routine report filed through PUC
Where
15 nm north (360°) of PUC
Time
01:23 UTC
Height
at 14,000 ft
Aircraft
S22T
Temperature
−16 °C
Icing
moderate rime zlc
SW4 at 15,000 ft, 34 nm southwest, 6:39 pm PDT (01:39 UTC): moderate turbulence, light rime icing, freezing, rain, 0 °C, remarks: instrument conditions ZDVWC-36. 857 nm along the route, 34 nm southwest of the line.
as filed, and in English
```
CEZ UA /OV CEZ030030/TM 0139/FL150/TP SW4/SK BASE150/WX FZ RA/TA 00/TB CONS MOD/IC LGT RIME/RM IMC ZDVWC-36
```
Report
a routine report filed through CEZ
Where
30 nm northeast (030°) of CEZ
Time
01:39 UTC
Height
at 15,000 ft
Aircraft
SW4
Sky
BASE150
Weather
freezing, rain
Temperature
0 °C
Turbulence
continuous moderate
Icing
light rime
Remarks
instrument conditions ZDVWC-36
SB20 at 16,000 ft, 43 nm northeast, 6:52 pm PDT (01:52 UTC): remarks: zse. At the departure end, 43 nm northeast of the line.
as filed, and in English
```
PAE UA /OV PAE075045/TM 0152/FL160/TP SB20/SK TOP120/RM ZSE
```
Report
a routine report filed through PAE
Where
45 nm east (075°) of PAE
Time
01:52 UTC
Height
at 16,000 ft
Aircraft
SB20
Sky
TOP120
Remarks
zse
A321 at 13,500 ft, 15 nm southwest, 6:54 pm PDT (01:54 UTC): remarks: zse. At the departure end, 15 nm southwest of the line.
as filed, and in English
```
SEA UA /OV SEA120045/TM 0154/FL135/TP A321/SK TOP130/RM ZSE
```
Report
a routine report filed through SEA
Where
45 nm southeast (120°) of SEA
Time
01:54 UTC
Height
at 13,500 ft
Aircraft
A321
Sky
TOP130
Remarks
zse
PC12 at 13,000 ft, 15 nm southwest, 5:42 pm PDT (00:42 UTC): remarks: zse. At the departure end, 15 nm southwest 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, 15 nm southwest, 5:42 pm PDT (00:42 UTC): remarks: zse. At the departure end, 15 nm southwest 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
C337 at 12,000 ft, 16 nm southwest, 6:18 pm PDT (01:18 UTC): light rime icing, -12 °C, remarks: zse. 110 nm along the route, 16 nm southwest 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 13,500 ft, 41 nm northeast, 6:08 pm PDT (01:08 UTC): no turbulence, a trace of icing, overcast from 9,000 ft to 13,500 ft, -10 °C. 139 nm along the route, 41 nm northeast 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
PC12 at 6,000 ft, 17 nm northeast, 5:56 pm PDT (00:56 UTC): overcast above 6,000 ft. 189 nm along the route, 17 nm northeast 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 14,000 ft, 33 nm southwest, 7:13 pm PDT (02:13 UTC): light turbulence up to 21,000 ft, light rime icing from 10,000 ft to 14,000 ft, -10 °C. 398 nm along the route, 33 nm southwest of the line.
as filed, and in English
```
BOI UA /OV BOI117049/TM 0213/FL140/TP PC12/TA M10/TB CONS LGT 210 BLO/IC LGT RIME 140-100 /ZLC
```
Report
a routine report filed through BOI
Where
49 nm southeast (117°) of BOI
Time
02:13 UTC
Height
at 14,000 ft
Aircraft
PC12
Temperature
−10 °C
Turbulence
continuous light at 21,000 ft below
Icing
light rime from 14,000 ft to 10,000 ft zlc
E175 at 5,900 ft, 23 nm northeast, 8:29 pm PDT (03:29 UTC): a broken layer above 5,900 ft, remarks: during the descent runway 31. 418 nm along the route, 23 nm northeast of the line.
as filed, and in English
```
SUN UA /OV KSUN/TM 0329/FL059/TP E175/SK BKN059-TOPUNKN/RM DURD RY31
```
Report
a routine report filed through SUN
Where
over KSUN
Time
03:29 UTC
Height
at 5,900 ft
Aircraft
E175
Sky
a broken layer from 5,900 ft, tops unknown
Remarks
during the descent runway 31
E175 at 5,700 ft, 23 nm northeast, 7:59 pm PDT (02:59 UTC): a broken layer above 5,700 ft, remarks: during the descent runway 31. 418 nm along the route, 23 nm northeast of the line.
as filed, and in English
```
SUN UA /OV KSUN/TM 0259/FL057/TP E175/SK BKN057-TOPUNKN/RM DURD RY31
```
Report
a routine report filed through SUN
Where
over KSUN
Time
02:59 UTC
Height
at 5,700 ft
Aircraft
E175
Sky
a broken layer from 5,700 ft, tops unknown
Remarks
during the descent runway 31
PC12 at 6,000 ft, 23 nm northeast, 6:09 pm PDT (01:09 UTC): scattered clouds up to 6,000 ft, remarks: multiple scattered layers during the descent runway 31. 418 nm along the route, 23 nm northeast 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

10 more routine reports are on the map.

Winds aloft along the route, and the time en route the forecast for use 02:00–09:00 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 12 forecast points nearest it (SEA, YKM, LWS, BOI, PIH, SLC, GJT, ALS, TCC, LBB, ABI, SAT). A plus sign is a headwind, a minus sign a tailwind.

Height	Average wind	Head- or tailwind	Temperature	Ground speed	Time en route	Arrival
5,500 ft	200° at 12 kt	+6 kt	11 °C	114 kt	13 h 33 min	12:08 pm CDT (17:08 UTC)
7,500 ft	210° at 13 kt	+4 kt	6 °C	116 kt	13 h 19 min	11:54 am CDT (16:54 UTC)
9,500 ft	220° at 12 kt	+1 kt	4 °C	119 kt	12 h 58 min	11:33 am CDT (16:33 UTC)
11,500 ft	230° at 17 kt	−1 kt	1 °C	121 kt	12 h 46 min	11:21 am CDT (16:21 UTC)
13,500 ft	230° at 20 kt	0	-3 °C	120 kt	12 h 52 min	11:27 am CDT (16:27 UTC)
15,500 ft	220° at 23 kt	+1 kt	-7 °C	119 kt	12 h 58 min	11:33 am CDT (16:33 UTC)
17,500 ft	220° at 27 kt	+2 kt	-11 °C	118 kt	13 h 05 min	11:40 am CDT (16:40 UTC)
18,000 ft FL180	220° at 28 kt	+3 kt	-12 °C	117 kt	13 h 12 min	11:47 am CDT (16:47 UTC)
24,000 ft FL240	220° at 34 kt	+2 kt	-22 °C	118 kt	13 h 05 min	11:40 am CDT (16:40 UTC)
30,000 ft FL300	240° at 41 kt	−8 kt	-30 °C	128 kt	12 h 04 min	10:39 am CDT (15:39 UTC)
34,000 ft FL340	240° at 43 kt	−11 kt	-36 °C	131 kt	11 h 47 min	10:22 am CDT (15:22 UTC)
39,000 ft FL390	240° at 39 kt	−10 kt	-45 °C	130 kt	11 h 53 min	10:28 am CDT (15:28 UTC)

Based on data from the 12th at 00:00 UTC; valid on the 12th at 06:00 UTC for use 02:00 to 09:00 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
SEA	used from 0 nm out; 23 nm from the line	050/7	050/11 1°	050/12 -5°	030/31 -7°	010/61 -15°	010/69 -26°	360/73 -40°	360/62 -47°	330/21 -43°
YKM	used from 50 nm out; 18 nm from the line	070/10	040/15 -1°	020/27 -8°	030/25 -13°	020/48 -20°	010/83 -27°	010/77 -37°	010/49 -40°	350/14 -41°
LWS	used from 199 nm out; 79 nm from the line	070/10	080/12 -2°	030/12 -6°	080/7 -10°	170/34 -21°	160/46 -32°	200/33 -35°	220/22 -35°	230/18 -38°
BOI	used from 249 nm out; 80 nm from the line		300/7 2°	280/5 -4°	210/16 -9°	210/60 -20°	210/75 -29°	210/63 -32°	220/64 -32°	220/54 -39°
PIH	used from 448 nm out; 50 nm from the line		L/V	240/13 1°	240/15 -3°	210/42 -15°	200/70 -25°	220/74 -29°	220/71 -36°	220/62 -43°
SLC	used from 548 nm out; 39 nm from the line		200/5	230/8 2°	220/20 -2°	210/40 -12°	190/53 -25°	210/62 -30°	220/69 -34°	220/64 -43°
GJT	used from 697 nm out; 62 nm from the line			210/43 7°	230/45 1°	220/49 -12°	220/62 -22°	220/59 -28°	230/60 -33°	220/55 -45°
ALS	used from 847 nm out; 78 nm from the line				230/37 4°	220/54 -9°	230/62 -22°	240/77 -26°	240/74 -33°	230/59 -45°
TCC	used from 1046 nm out; 51 nm from the line		210/42	230/33 14°	230/32 6°	220/35 -6°	230/49 -19°	240/72 -27°	250/62 -36°	250/52 -48°
LBB	used from 1195 nm out; 36 nm from the line		200/36 18°	220/19 15°	240/20 8°	230/24 -4°	240/37 -16°	250/57 -28°	250/51 -38°	270/47 -50°
ABI	used from 1295 nm out; 79 nm from the line		200/31 17°	210/21 15°	240/15 9°	250/14 -4°	250/24 -14°	250/36 -28°	270/35 -38°	290/41 -50°
SAT	used from 1444 nm out; 75 nm from the line	150/26	180/18 19°	180/18 14°	200/14 9°	230/16 -6°	210/9 -13°	270/8 -29°	280/6 -39°	340/19 -51°

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
BFI Seattle, WA	departure	VFR	calm	10+ mi	none	21 ft	7:53 pm PDT (02:53 UTC)
YKM Yakima, WA	90 nm out, 4 nm south of the line, tower	VFR Sky: overcast at 8,500 feet	calm	10+ mi	8,500 ft	1,098 ft	02:53 UTC
PDT Pendleton, OR	179 nm out, 2 nm south of the line, tower	VFR Sky: a broken layer at 6,500 feet, overcast at 8,000 feet	from the southwest (220°) at 3 knots	10+ mi	6,500 ft	1,494 ft	02:53 UTC
SUN Hailey, ID	418 nm out, 23 nm northeast of the line, tower	IFR Sky: a broken layer at 700 feet, a broken layer at 1,100 feet, overcast at 2,200 feet Weather: light rain	from the east-southeast (120°) at 4 knots	7 mi	700 ft	5,319 ft	03:20 UTC
OGD Ogden, UT	578 nm out, 12 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	4,472 ft	02:53 UTC
HCR Heber, UT	627 nm out, 25 nm southwest of the line	VFR Sky: a few clouds at 4,500 feet, overcast at 6,000 feet Weather: light rain	from the southwest (230°) at 4 knots	7 mi	6,000 ft	5,636 ft	03:15 UTC
GJT Grand Junction, CO	787 nm out, 11 nm northeast of the line, tower	VFR Sky: a few clouds at 8,500 feet, a few clouds at 11,000 feet	variable at 3 knots	10+ mi	none	4,861 ft	02:53 UTC
SKX Taos, NM	996 nm out, 4 nm west of the line	no report just now				7,094 ft
LLN Levelland, TX	1235 nm out, 5 nm north of the line	VFR	from the south (170°) at 13 knots, gusting to 21	8 mi	none	3,514 ft	03:15 UTC
BFE Brownfield, TX	1255 nm out, 6 nm southwest of the line	no report just now				3,264 ft
SJT San Angelo, TX	1394 nm out, 12 nm southwest of the line, tower	VFR	from the south (170°) at 8 knots	10+ mi	none	1,918 ft	02:51 UTC
SAT San Antonio, TX	destination	VFR Sky: a few clouds at 20,000 feet	from the southeast (140°) at 12 knots, gusting to 20	10+ mi	none	809 ft	9:51 pm CDT (02:51 UTC)

The highest airport on this list sits at 7,094 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.

At SAT when you get there the forecast at the estimated arrival, 10:22 am CDT (15:22 UTC)

Wind from the east-southeast at 5 knots, visibility more than 6 miles, a broken layer at 1,200 feet marginal VFR

The whole forecast for SAT

From Sun 10:00 pm CDT (03:00 UTC): wind from the south-southeast at 15 knots, visibility more than 6 miles, a few clouds at 6,000 feet, scattered clouds at 25,000 feet
From Mon 12:00 am CDT (05:00 UTC): wind from the southeast at 9 knots, visibility more than 6 miles, scattered clouds at 1,200 feet
From Mon 6:00 am CDT (11:00 UTC): wind from the east-southeast at 5 knots, visibility more than 6 miles, a broken layer at 1,200 feet
From Mon 12:00 pm CDT (17:00 UTC): wind from the south-southeast at 8 knots, visibility more than 6 miles, a broken layer at 2,500 feet
From Mon 2:00 pm CDT (19:00 UTC): wind from the south at 11 knots, visibility more than 6 miles, a broken layer at 5,000 feet

The forecast for BFI, the departure

From Sun 8:00 pm PDT (03:00 UTC): wind calm, visibility more than 6 miles, clear skies
From Mon 3:00 am PDT (10:00 UTC): wind calm, 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

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

6/4240 SAN ANGELO, TX, Sunday, March 8, 2026 through Sunday, November 1, 2026 Local 6 nm from the route, 1404 nm along the route · security · until 1 November · ZFW

Daylight

Sunset at BFI 6:27 pm PDT (01:27 UTC), at SAT 7:06 pm CDT (00:06 UTC) (civil twilight ends 7:30 pm CDT (00:30 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 southern Rockies · loop National Weather Service

Radar now, the southern Plains · 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: Boeing Fld/King County International, San Antonio International.