San Antonio International to Boeing Fld/King County International SAT → BFI
1,544 nautical miles (1,777 statute miles) northwest on a straight line, true course 321°, about 317° magnetic at the departure end (variation 4E). At 120 knots that is 12 h 09 min at the quickest height in today's winds (4,500 ft, a 7-knot tailwind), arriving about 12:15 pm PDT (19:15 UTC). 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
- AIRMET TANGO 4W: moderate turbulence below 18,000 ft up to 18,000 ft. Over the route from 438 to 936 nm out.
- AIRMET TANGO 2W: moderate turbulence above 18,000 ft from 35,000 ft to 45,000 ft. Over the route from 468 to 647 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 637 to 747 nm out.
- AIRMET TANGO 4W: moderate turbulence above 18,000 ft from 18,000 ft to 38,000 ft. Over the route from 667 to 916 nm out.
- AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the route from 747 to 1355 nm out.
- AIRMET ZULU 2C: moderate icing up to 23,000 ft. Over the route from 787 to 1195 nm out.
- AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 36,000 ft. Over the route from 1086 to 1245 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, 1155 nm along the route.
- AIRMET ZULU 2C: moderate icing up to 23,000 ft. Over the route from 1265 to 1424 nm out.
- AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 39,000 ft. Over the last 209 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 SAT.
Pilot reports along the route within 50 nm of the line, last three hours, the serious ones first
Not fetched just now.
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 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 12 forecast points nearest it (SAT, ABI, LBB, TCC, ALS, GJT, SLC, PIH, BOI, 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 | 200° at 12 kt | −7 kt | 11 °C | 127 kt | 12 h 09 min | 12:15 pm PDT (19:15 UTC) |
| 6,500 ft | 200° at 11 kt | −5 kt | 7 °C | 125 kt | 12 h 21 min | 12:27 pm PDT (19:27 UTC) |
| 8,500 ft | 220° at 12 kt | −2 kt | 5 °C | 122 kt | 12 h 39 min | 12:45 pm PDT (19:45 UTC) |
| 10,500 ft | 230° at 16 kt | 0 | 2 °C | 120 kt | 12 h 52 min | 12:58 pm PDT (19:58 UTC) |
| 12,500 ft | 230° at 18 kt | 0 | -1 °C | 120 kt | 12 h 52 min | 12:58 pm PDT (19:58 UTC) |
| 14,500 ft | 230° at 21 kt | −1 kt | -5 °C | 121 kt | 12 h 46 min | 12:52 pm PDT (19:52 UTC) |
| 16,500 ft | 220° at 25 kt | −2 kt | -9 °C | 122 kt | 12 h 39 min | 12:45 pm PDT (19:45 UTC) |
| 18,000 ft FL180 | 220° at 28 kt | −3 kt | -12 °C | 123 kt | 12 h 33 min | 12:39 pm PDT (19:39 UTC) |
| 24,000 ft FL240 | 220° at 34 kt | −2 kt | -22 °C | 122 kt | 12 h 39 min | 12:45 pm PDT (19:45 UTC) |
| 30,000 ft FL300 | 240° at 41 kt | +7 kt | -30 °C | 113 kt | 13 h 40 min | 1:46 pm PDT (20:46 UTC) |
| 34,000 ft FL340 | 240° at 43 kt | +11 kt | -36 °C | 109 kt | 14 h 10 min | 2:16 pm PDT (21:16 UTC) |
| 39,000 ft FL390 | 240° at 39 kt | +9 kt | -45 °C | 111 kt | 13 h 55 min | 2:01 pm PDT (21:01 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 |
|---|---|---|---|---|---|---|---|---|---|---|
| SAT | used from 0 nm out; 25 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° |
| ABI | used from 100 nm out; 78 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° | |
| LBB | used from 249 nm out; 38 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° | |
| TCC | used from 349 nm out; 57 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° | |
| ALS | used from 498 nm out; 84 nm from the line | 230/37 4° | 220/54 -9° | 230/62 -22° | 240/77 -26° | 240/74 -33° | 230/59 -45° | |||
| GJT | used from 697 nm out; 40 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° | ||
| SLC | used from 847 nm out; 78 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° | |
| PIH | used from 996 nm out; 55 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° | |
| BOI | used from 1096 nm out; 81 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° | |
| LWS | used from 1295 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° |
| YKM | used from 1345 nm out; 82 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° |
| SEA | used from 1494 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° |
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 |
|---|---|---|---|---|---|---|---|
| SAT San Antonio, TX | departure | no report just now | 809 ft | ||||
| SJT San Angelo, TX | 149 nm out, 12 nm southwest of the line, tower | no report just now | 1,918 ft | ||||
| BFE Brownfield, TX | 289 nm out, 6 nm southwest of the line | no report just now | 3,264 ft | ||||
| LLN Levelland, TX | 309 nm out, 5 nm north of the line | no report just now | 3,514 ft | ||||
| SKX Taos, NM | 548 nm out, 4 nm west of the line | no report just now | 7,094 ft | ||||
| GJT Grand Junction, CO | 757 nm out, 11 nm northeast of the line, tower | no report just now | 4,861 ft | ||||
| HCR Heber, UT | 916 nm out, 25 nm southwest of the line | no report just now | 5,636 ft | ||||
| OGD Ogden, UT | 966 nm out, 12 nm southwest of the line, tower | no report just now | 4,472 ft | ||||
| SUN Hailey, ID | 1125 nm out, 23 nm northeast of the line, tower | no report just now | 5,319 ft | ||||
| PDT Pendleton, OR | 1365 nm out, 2 nm south of the line, tower | no report just now | 1,494 ft | ||||
| YKM Yakima, WA | 1454 nm out, 4 nm south of the line, tower | no report just now | 1,098 ft | ||||
| BFI Seattle, WA | destination | no report just now | 21 ft |
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 BFI when you get there the forecast at the estimated arrival, 12:15 pm PDT (19:15 UTC)
BFI has no terminal forecast; use the nearest airport that does.
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, 139 nm along the route · security · until 1 November · ZFW
Daylight
Sunset at SAT 7:05 pm CDT (00:05 UTC), at BFI 6:25 pm PDT (01:25 UTC) (civil twilight ends 6:56 pm PDT (01:56 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
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: San Antonio International, Boeing Fld/King County International.