Plan a flight · Tue 1:54 am MDT (07:54 UTC)

Billings Logan International to Boeing Fld/King County International BIL → BFI

575 nautical miles (662 statute miles) west on a straight line, true course 285°, about 275° magnetic at the departure end (variation 10E). At 120 knots that is 4 h 45 min at the quickest height in today's winds (18,000 ft, a 1-knot tailwind), arriving about 5:39 am PDT (12:39 UTC), after sunset at the destination. Right now BIL is marginal VFR, wind from the north (010°) at 3 knots; BFI is VFR, wind from the southeast (140°) at 7 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: 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 SIERRA 1E: mountains obscured by cloud (due to mountains obscured by clouds, precipitation, mist). Over the route from 10 to 89 nm out.
AIRMET SIERRA 7E: low cloud or poor visibility (IFR conditions) (due to ceilings below 1,000 ft, visibility below 3 miles, mist). Over the route from 60 to 169 nm out.
AIRMET TANGO 1W: moderate turbulence above 18,000 ft from 18,000 ft to 39,000 ft. Over the route from 218 to 268 nm out.

Turbulence AIRMET in force: moderate turbulence from 18,000 ft to 39,000 ft, over the route from 218 to 268 nm out. No pilot has reported turbulence near the line in the last three hours. The government's turbulence forecast map ↗

Icing No icing warning in force along the route. No pilot has reported icing near the line in the last three hours. The freezing level is below 4,500 ft, the lowest forecast height, so any cloud could carry ice. The government's icing forecast map ↗

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 BIL.

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 7 forecast points nearest it (BIL, GTF, DLN, LWS, GEG, 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	290° at 5 kt	+4 kt	0 °C	116 kt	4 h 57 min	5:51 am PDT (12:51 UTC)
6,500 ft	300° at 6 kt	+6 kt	1 °C	114 kt	5 h 03 min	5:57 am PDT (12:57 UTC)
8,500 ft	310° at 6 kt	+5 kt	-1 °C	115 kt	5 h	5:54 am PDT (12:54 UTC)
10,500 ft	310° at 5 kt	+4 kt	-1 °C	116 kt	4 h 57 min	5:51 am PDT (12:51 UTC)
12,500 ft	320° at 4 kt	+2 kt	-4 °C	118 kt	4 h 52 min	5:46 am PDT (12:46 UTC)
14,500 ft	350° at 6 kt	+1 kt	-8 °C	119 kt	4 h 50 min	5:44 am PDT (12:44 UTC)
16,500 ft	010° at 9 kt	0	-13 °C	120 kt	4 h 48 min	5:42 am PDT (12:42 UTC)
18,000 ft FL180	010° at 11 kt	−1 kt	-16 °C	121 kt	4 h 45 min	5:39 am PDT (12:39 UTC)
24,000 ft FL240	360° at 9 kt	+1 kt	-28 °C	119 kt	4 h 50 min	5:44 am PDT (12:44 UTC)
30,000 ft FL300	360° at 21 kt	+2 kt	-40 °C	118 kt	4 h 52 min	5:46 am PDT (12:46 UTC)
34,000 ft FL340	350° at 15 kt	+3 kt	-45 °C	117 kt	4 h 55 min	5:49 am PDT (12:49 UTC)
39,000 ft FL390	250° at 10 kt	+7 kt	-48 °C	113 kt	5 h 05 min	5:59 am PDT (12:59 UTC)

Based on data from the 13th at 00:00 UTC; valid on the 13th 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
BIL	used from 0 nm out; 25 nm from the line		270/8	250/11 1°	230/15 -2°	260/18 -15°	220/45 -28°	230/53 -39°	220/48 -41°	220/51 -43°
GTF	used from 99 nm out; 70 nm from the line		260/12	270/12 0°	290/10 -3°	L/V -16°	270/12 -30°	250/6 -40°	240/23 -41°	220/24 -44°
DLN	used from 149 nm out; 75 nm from the line			L/V -3°	180/8 -3°	160/17 -17°	200/26 -31°	210/18 -38°	190/28 -41°	210/27 -44°
LWS	used from 248 nm out; 89 nm from the line	L/V	280/6 0°	290/9 -2°	L/V -4°	030/24 -17°	030/33 -29°	030/69 -40°	030/49 -46°	L/V -46°
GEG	used from 347 nm out; 32 nm from the line		350/6 0°	350/6 -1°	360/8 -4°	020/24 -16°	030/45 -26°	020/57 -41°	020/53 -50°	340/6 -48°
YKM	used from 446 nm out; 57 nm from the line	L/V	320/6 3°	020/7 0°	020/14 -2°	020/36 -14°	020/46 -25°	010/56 -40°	360/59 -50°	360/24 -53°
SEA	used from 496 nm out; 55 nm from the line	L/V	320/7 3°	350/15 3°	350/17 -1°	360/27 -14°	350/31 -24°	350/39 -40°	340/43 -49°	360/42 -59°

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
BIL Billings, MT	departure	marginal VFR Sky: overcast at 1,400 feet	from the north (010°) at 3 knots	10+ mi	1,400 ft	3,662 ft	12:53 am MDT (06:53 UTC)
HWQ Harlowton, MT	60 nm out, 23 nm north of the line	no report just now				4,311 ft
HLN Helena, MT	149 nm out, 12 nm north of the line, tower	VFR	from the west (270°) at 3 knots	10+ mi	none	3,877 ft	06:53 UTC
MSO Missoula, MT	238 nm out, 12 nm north of the line, tower	VFR Sky: overcast at 4,100 feet	from the north (350°) at 3 knots	10+ mi	4,100 ft	3,205 ft	06:53 UTC
PUW Pullman/Moscow, WA	357 nm out, 21 nm south of the line	VFR	calm	10+ mi	none	2,566 ft	06:53 UTC
MWH Moses Lake, WA	456 nm out, 7 nm southeast of the line, tower	VFR	calm	10+ mi	none	1,188 ft	06:52 UTC
EAT Wenatchee, WA	486 nm out, 4 nm northwest of the line	reported, no category	calm		none	1,248 ft	06:55 UTC
ESW Easton, WA	526 nm out, 12 nm south of the line	no report just now				2,226 ft
BFI Seattle, WA	destination	VFR Sky: overcast at 9,000 feet	from the southeast (140°) at 7 knots	10+ mi	9,000 ft	21 ft	11:53 pm PDT (06:53 UTC)

The highest airport on this list sits at 4,311 ft; the ground between airports is higher still. Check the sectional chart for the terrain and the minimum safe heights along the line.

The codes as issued, and in English, for every airport in the table

BIL Billings, MT