Plan a flight · Mon 4:30 am PDT (11:30 UTC)

Boeing Fld/King County International to Luis Munoz Marin International BFI → SJU

3,238 nautical miles (3,726 statute miles) east on a straight line, true course 102°, about 087° magnetic at the departure end (variation 15E). At 120 knots that is 22 h 02 min at the quickest height in today's winds (34,000 ft, a 27-knot tailwind), arriving about 5:32 am AST (09:32 UTC), after sunset at the destination. Right now BFI is VFR, wind calm; SJU is VFR, 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: 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

SIGMET E35E: thunderstorms (a convective SIGMET) up to 38,000 ft, moving from the west at 20 knots, until 5:55 am PDT (12:55 UTC). Over the route from 2319 to 2359 nm out.

as issued

WSUS31 KKCI 121055
MKCE WST 121055
CONVECTIVE SIGMET 35E
VALID UNTIL 1255Z
FL CSTL WTRS
FROM 160E OMN-200ENE TRV-60ENE PBI-50ENE TRV-160E OMN
AREA TS MOV FROM 26020KT. TOPS TO FL380.

AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 39,000 ft. Over the route from 30 to 330 nm out.
AIRMET ZULU 2C: moderate icing up to 18,000 ft. Over the route from 180 to 480 nm out.
AIRMET SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the route from 190 to 700 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). Over the route from 320 to 1009 nm out.
AIRMET ZULU 2C: moderate icing up to 23,000 ft. Over the route from 500 to 680 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 750 to 880 nm out.
AIRMET TANGO 4W: moderate turbulence above 18,000 ft (due to mountain wave) from 34,000 ft to 43,000 ft. Near the route, 800 nm along the route.
AIRMET TANGO 2W: 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 1009 to 1439 nm out.
AIRMET SIERRA 3E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, precipitation, mist). Over the route from 1759 to 1819 nm out.
AIRMET TANGO 2W: moderate turbulence above 18,000 ft from 30,000 ft to 41,000 ft. Over the route from 2019 to 2219 nm out.

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

B38M at 38,000 ft, 31 nm southwest, 4:00 am PDT (11:00 UTC): moderate turbulence, no icing, remarks: ztlfd 22. 1979 nm along the route, 31 nm southwest of the line.
as filed, and in English
```
ATL UA /OV VNA/TM 1100/FL380/TP B38M/TB MOD/IC NEG/RM ZTLFD 22
```
Report
a routine report filed through ATL
Where
over VNA
Time
11:00 UTC
Height
at 38,000 ft
Aircraft
B38M
Turbulence
moderate
Icing
none
Remarks
ztlfd 22
B752 at 33,000 ft, 16 nm southwest, 3:13 am PDT (10:13 UTC): no chop turbulence above 33,000 ft. 2039 nm along the route, 16 nm southwest of the line.
as filed, and in English
```
AMG UA /OV AMG360020/TM 1013/FL330/TP B752/TB NEG CHOP 330
```
Report
a routine report filed through AMG
Where
20 nm north (360°) of AMG
Time
10:13 UTC
Height
at 33,000 ft
Aircraft
B752
Turbulence
no chop at 33,000 ft
B752 at 35,000 ft, 31 nm southwest, 4:13 am PDT (11:13 UTC): light chop turbulence. 2049 nm along the route, 31 nm southwest of the line.
as filed, and in English
```
AMG UA /OV AMG/TM 1113/FL350/TP B752/TB OCNL LGT CHOP
```
Report
a routine report filed through AMG
Where
over AMG
Time
11:13 UTC
Height
at 35,000 ft
Aircraft
B752
Turbulence
occasional light chop
C182 at 8,000 ft, 35 nm southwest, 3:45 am PDT (10:45 UTC): no turbulence, no icing, clear from 8,000 ft to 60,000 ft. 2069 nm along the route, 35 nm southwest of the line.
as filed, and in English
```
AYS UA /OV AYS090015/TM 1045/FL080/TP C182/SK SKC/TB NEG/IC NEG
```
Report
a routine report filed through AYS
Where
15 nm east (090°) of AYS
Time
10:45 UTC
Height
at 8,000 ft
Aircraft
C182
Sky
clear
Turbulence
none
Icing
none

Winds aloft along the route, and the time en route the forecast for use 08:00–15:00 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 20 forecast points nearest it (SEA, YKM, LWS, DLN, BIL, LND, RAP, BFF, ONL, GRI, MKC, COU, CGI, BNA, HSV, ATL, SAV, JAX, MLB, MIA). A plus sign is a headwind, a minus sign a tailwind.

Height	Average wind	Head- or tailwind	Temperature	Ground speed	Time en route	Arrival
3,500 ft	280° at 10 kt	−10 kt		130 kt	24 h 54 min	8:24 am AST (12:24 UTC)
5,500 ft	280° at 12 kt	−10 kt	21 °C	130 kt	24 h 54 min	8:24 am AST (12:24 UTC)
7,500 ft	270° at 10 kt	−9 kt	12 °C	129 kt	25 h 06 min	8:36 am AST (12:36 UTC)
9,500 ft	270° at 10 kt	−9 kt	8 °C	129 kt	25 h 06 min	8:36 am AST (12:36 UTC)
11,500 ft	260° at 10 kt	−9 kt	5 °C	129 kt	25 h 06 min	8:36 am AST (12:36 UTC)
13,500 ft	260° at 11 kt	−9 kt	1 °C	129 kt	25 h 06 min	8:36 am AST (12:36 UTC)
15,500 ft	260° at 12 kt	−9 kt	-4 °C	129 kt	25 h 06 min	8:36 am AST (12:36 UTC)
17,500 ft	260° at 12 kt	−9 kt	-8 °C	129 kt	25 h 06 min	8:36 am AST (12:36 UTC)
18,000 ft FL180	260° at 12 kt	−9 kt	-9 °C	129 kt	25 h 06 min	8:36 am AST (12:36 UTC)
24,000 ft FL240	250° at 18 kt	−11 kt	-21 °C	131 kt	24 h 43 min	8:13 am AST (12:13 UTC)
30,000 ft FL300	270° at 27 kt	−23 kt	-32 °C	143 kt	22 h 39 min	6:09 am AST (10:09 UTC)
34,000 ft FL340	270° at 32 kt	−27 kt	-39 °C	147 kt	22 h 02 min	5:32 am AST (09:32 UTC)
39,000 ft FL390	270° at 30 kt	−26 kt	-48 °C	146 kt	22 h 11 min	5:41 am AST (09:41 UTC)

Based on data from the 12th at 06:00 UTC; valid on the 12th at 12:00 UTC for use 08:00 to 15:00 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; 25 nm from the line	350/5	010/6 0°	010/9 -4°	010/27 -6°	010/51 -15°	360/58 -26°	360/60 -41°	350/55 -48°	340/30 -45°
YKM	used from 50 nm out; 41 nm from the line	360/6	360/11 -1°	030/20 -7°	040/21 -11°	020/55 -18°	010/84 -26°	010/79 -40°	010/45 -42°	350/23 -42°
LWS	used from 150 nm out; 54 nm from the line	L/V	340/5 -3°	L/V -6°	040/7 -10°	100/23 -22°	180/30 -31°	190/11 -34°	200/11 -36°	220/23 -40°
DLN	used from 350 nm out; 54 nm from the line			190/10 -4°	220/23 -4°	210/21 -18°	210/43 -28°	210/60 -33°	210/72 -37°	210/67 -44°
BIL	used from 500 nm out; 86 nm from the line		300/14	270/19 -2°	260/26 -2°	220/28 -13°	210/51 -25°	220/56 -33°	220/61 -39°	220/72 -45°
LND	used from 650 nm out; 106 nm from the line			240/10 3°	240/30 0°	220/42 -13°	230/52 -23°	220/54 -33°	220/52 -36°	220/53 -44°
RAP	used from 700 nm out; 125 nm from the line		250/28 16°	260/31 10°	240/25 4°	210/35 -10°	200/45 -23°	230/47 -31°	230/47 -36°	230/51 -46°
BFF	used from 800 nm out; 68 nm from the line		280/28	260/39 11°	240/34 5°	210/38 -11°	210/52 -22°	230/61 -31°	230/61 -36°	240/56 -45°
ONL	used from 949 nm out; 101 nm from the line		250/31 22°	230/27 16°	220/25 8°	230/25 -9°	220/29 -22°	250/42 -33°	250/48 -36°	250/52 -46°
GRI	used from 999 nm out; 75 nm from the line		230/39 23°	230/32 15°	210/29 7°	230/31 -8°	230/43 -21°	250/52 -31°	260/59 -35°	260/59 -46°
MKC	used from 1199 nm out; 78 nm from the line	240/49	240/21 20°	220/19 13°	230/21 6°	260/26 -7°	250/37 -19°	270/66 -31°	270/65 -38°	280/60 -48°
COU	used from 1349 nm out; 52 nm from the line	250/36	260/14 16°	250/5 12°	260/12 6°	260/24 -7°	260/35 -19°	280/58 -31°	280/62 -40°	290/60 -49°
CGI	used from 1499 nm out; 51 nm from the line	260/22	250/15 15°	250/13 11°	250/16 6°	270/29 -7°	280/30 -18°	290/40 -31°	290/55 -40°	300/51 -51°
BNA	used from 1649 nm out; 73 nm from the line	300/20	300/14 15°	300/14 10°	300/13 4°	310/22 -5°	280/24 -18°	310/37 -33°	310/50 -41°	320/49 -51°
HSV	used from 1699 nm out; 43 nm from the line	300/20	310/14 16°	310/18 10°	310/15 4°	320/19 -5°	290/16 -18°	320/36 -32°	320/47 -41°	330/42 -50°
ATL	used from 1849 nm out; 21 nm from the line	330/32	340/36 17°	350/34 10°	340/25 6°	330/27 -6°	350/35 -18°	330/49 -32°	340/47 -41°	340/27 -51°
SAV	used from 1999 nm out; 66 nm from the line	330/16	310/15 14°	320/23 10°	310/30 7°	310/30 -6°	300/28 -19°	270/25 -32°	300/25 -39°	320/26 -50°
JAX	used from 2099 nm out; 53 nm from the line	310/22	310/19 16°	300/22 14°	290/25 8°	300/25 -7°	300/24 -18°	270/20 -33°	260/25 -41°	290/17 -51°
MLB	used from 2249 nm out; 130 nm from the line	290/10	260/15 18°	290/12 13°	280/13 8°	250/20 -7°	260/18 -18°	240/17 -32°	250/20 -41°	250/22 -52°
MIA	used from 2449 nm out; 251 nm from the line	L/V	L/V 17°	L/V 13°	L/V 8°	270/6 -6°	250/9 -17°	290/17 -32°	280/25 -41°	280/21 -52°

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	3:53 am PDT (10:53 UTC)
MWH Moses Lake, WA	120 nm out, 10 nm northeast of the line, tower	VFR	from the north-northwest (340°) at 6 knots	10+ mi	none	1,188 ft	10:52 UTC
RVF Twin Bridges, MT	430 nm out, 0 nm southwest of the line	marginal VFR Sky: overcast at 2,400 feet	from the north-northeast (020°) at 17 knots	10+ mi	2,400 ft	4,788 ft	11:15 UTC
CDR Chadron, NE	860 nm out, 6 nm north of the line	low IFR Sky: overcast at 300 feet Weather: mist	from the north (360°) at 3 knots	3 mi	300 ft	3,297 ft	11:01 UTC
MCI Kansas City, MO	1289 nm out, 4 nm east of the line, tower	VFR	from the south-southwest (210°) at 14 knots, gusting to 24	10+ mi	none	1,027 ft	10:53 UTC
MKC Kansas City, MO	1299 nm out, 4 nm south of the line, tower	VFR	from the south-southwest (200°) at 13 knots	10+ mi	none	756 ft	10:54 UTC
ATL Atlanta, GA	1889 nm out, 9 nm northeast of the line, tower	VFR	from the northwest (310°) at 12 knots	10+ mi	none	1,026 ft	10:52 UTC
MCN Macon, GA	1959 nm out, 13 nm southwest of the line, tower	VFR	from the west-northwest (290°) at 5 knots	10+ mi	none	354 ft	10:53 UTC
SJU San Juan, PR	destination	VFR Sky: scattered clouds at 3,000 feet, scattered clouds at 4,500 feet	calm	10+ mi	none	9 ft	6:56 am AST (10:56 UTC)

The highest airport on this list sits at 4,788 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.

At SJU when you get there the forecast at the estimated arrival, 5:32 am AST (09:32 UTC)

Wind from the east-southeast at 6 knots, visibility more than 6 miles, showers nearby, scattered clouds at 3,000 feet, scattered clouds at 6,000 feet VFR

The whole forecast for SJU

From Mon 3:00 am AST (07:00 UTC): wind from the east-southeast at 6 knots, visibility more than 6 miles, light rain showers, thunderstorms nearby, scattered clouds at 2,500 feet (thunderheads), scattered clouds at 5,000 feet
From Mon 10:00 am AST (14:00 UTC): wind from the east at 11 knots, visibility more than 6 miles, showers nearby, a few clouds at 2,500 feet, scattered clouds at 4,000 feet
From Mon 1:00 pm AST (17:00 UTC): wind from the east at 13 knots, gusting to 20, visibility more than 6 miles, light rain showers, thunderstorms nearby, scattered clouds at 2,500 feet (thunderheads), a broken layer at 5,000 feet
From Mon 7:00 pm AST (23:00 UTC): wind from the east-southeast at 6 knots, visibility more than 6 miles, showers nearby, scattered clouds at 3,000 feet, scattered clouds at 6,000 feet

The forecast for BFI, the departure

From Mon 5:00 am PDT (12:00 UTC): wind light and variable, visibility more than 6 miles, clear skies
From Mon 12:00 pm PDT (19:00 UTC): wind from the west-southwest at 4 knots, visibility more than 6 miles, clear skies
From Mon 2:00 pm PDT (21:00 UTC): wind from the west-northwest at 5 knots, visibility more than 6 miles, clear skies
From Mon 8:00 pm PDT (03:00 UTC): wind calm, visibility more than 6 miles, scattered clouds at 25,000 feet
From Tue 4:00 am PDT (11:00 UTC): wind from the south-southeast at 4 knots, visibility more than 6 miles, overcast at 10,000 feet

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

6/8927 Kalispell, MT, Wednesday, October 14, 2026 through Wednesday, October 14, 2026 Local 24 nm from the route, 330 nm along the route · a VIP movement · starts Wednesday 14 October · ZSE
6/8923 Kalispell, MT, Wednesday, October 14, 2026 through Wednesday, October 14, 2026 Local 24 nm from the route, 330 nm along the route · a VIP movement · starts Wednesday 14 October · ZLC
6/4508 CEIBA, PR 24 nm from the route, at the destination end · security · ZSU

Daylight

Sunset at BFI 6:25 pm PDT (01:25 UTC), at SJU 6:03 pm AST (22:03 UTC) (civil twilight ends 6:25 pm AST (22:25 UTC)). At 120 knots the arrival at SJU is before sunrise there (6:17 am AST (10:17 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 now, the upper Mississippi valley · 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, Luis Munoz Marin International.