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2,744 km · Domestic

Seattle–Tacoma (SEA) – St. Louis Lambert (STL)

In July 2026, 244 flights operated between Seattle–Tacoma and St. Louis Lambert (both directions), and 80.7% left on time, according to the US BTS.

Official · July 2026 according to the US BTS only airlines required to report on-time data to the US DOT

Flights per month

Only complete months are shown. A month appears once the source has published every day of it.

The most recent periods19 periods
PeriodFlights operated 2025Flights operated 2026Change vs last year
January6673▲ 10.6%
February7675▼ 1.3%
March104102▼ 1.9%
April1181180.0%
May156162▲ 3.8%
June231236▲ 2.2%
July245244▼ 0.4%
August222––
September196––
October122–in progress
November99––
December107––
Year to date (Jan–Jul)9961,010▲ 1.4%

On-time departures by month

Departures within 15 minutes of schedule.

The most recent periods19 periods
PeriodOn-time departures 2025On-time departures 2026Change vs last year
January83.3%80.8%▼ 3.0%
February89.5%93.3%▲ 4.2%
March87.5%91.2%▲ 4.2%
April89.0%96.6%▲ 8.5%
May78.2%79.0%▲ 1.0%
June62.8%81.4%▲ 29.6%
July68.2%80.7%▲ 18.3%
August70.7%––
September80.6%––
October84.4%–in progress
November86.9%––
December76.6%––
Year-to-date average (Jan–Jul)79.8%86.1%▲ 8.0%

Cancelled flights by month

The most recent periods19 periods
PeriodCancelled flights 2025Cancelled flights 2026Change vs last year
January220.0%
February00–
March03–
April02–
May20▼ 100.0%
June10▼ 100.0%
July12▲ 100.0%
August0––
September0––
October0–in progress
November1––
December1––
Year to date (Jan–Jul)69▲ 50.0%

Airlines on this route

  1. Alaska Airlines 89.5%
  2. Southwest Airlines 10.5%

Oct 1, 2024 – Jul 31, 2026

By direction

SEA → STL

Scheduled flights
1,526
Flights operated
1,521
Cancelled
5 · 0.3%
On-time departures
80.9%

STL → SEA

Scheduled flights
1,527
Flights operated
1,515
Cancelled
12 · 0.8%
On-time departures
80.1%

SEA → STL and STL → SEA counted separately.

Airlines on this route

Oct 1, 2024 – Jul 31, 2026
AirlineScheduled flights Share On-time departures Cancelled
Alaska Airlines AS 2,733 89.5% 82.6% 16
Southwest Airlines WN 320 10.5% 63.0% 1

Shares are of scheduled flights in the period shown. Codeshare flights are counted once, under the operating airline.

Flight timing & delays

Historical departures, grouped by the scheduled local time at the departure airport. These are recorded outcomes, not a forecast for your flight.

Times are local to the departure airport of each flight; both directions are combined.

US domestic sectors recorded by BTS

Source: the US BTS · Oct 12, 2024 → Jul 31, 2026

Lowest average delay06:00–07:00-0.5min · 274 recorded · 273 measured
Gap to highest-delay hour12.2min06:00 ↔ 15:00
Recorded flights3,053SEA–STL

Departure hour

On-time departures Partial coverage: only airlines that report on-time data to the US DOT
00:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 01:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 02:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 03:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 04:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 05:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 06:00 · 92.7% · 274 recorded · 273 measured · Source: the US BTS 07:00 · 93.1% · 496 recorded · 491 measured · Source: the US BTS 08:00 · 88.5% · 303 recorded · 303 measured · Source: the US BTS 09:00 · Fewer than 200 measured departures · 192 recorded · 191 measured · Source: the US BTS 10:00 · Fewer than 200 measured departures · 20 recorded · 20 measured · Source: the US BTS 11:00 · Fewer than 200 measured departures · 189 recorded · 189 measured · Source: the US BTS 12:00 · Fewer than 200 measured departures · 168 recorded · 168 measured · Source: the US BTS 13:00 · Fewer than 200 measured departures · 54 recorded · 54 measured · Source: the US BTS 14:00 · 82.6% · 227 recorded · 224 measured · Source: the US BTS 15:00 · 77.0% · 295 recorded · 295 measured · Source: the US BTS 16:00 · Fewer than 200 measured departures · 96 recorded · 93 measured · Source: the US BTS 17:00 · Fewer than 200 measured departures · 88 recorded · 88 measured · Source: the US BTS 18:00 · 77.1% · 504 recorded · 502 measured · Source: the US BTS 19:00 · Fewer than 200 measured departures · 147 recorded · 145 measured · Source: the US BTS 20:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 21:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 22:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 23:00 · No observations · 0 recorded · 0 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Average departure delay Partial coverage: only airlines that report on-time data to the US DOT
00:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 01:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 02:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 03:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 04:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 05:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 06:00 · -0.5 min · 274 recorded · 273 measured · Source: the US BTS 07:00 · 2.2 min · 496 recorded · 491 measured · Source: the US BTS 08:00 · 3.2 min · 303 recorded · 303 measured · Source: the US BTS 09:00 · Fewer than 200 measured departures · 192 recorded · 191 measured · Source: the US BTS 10:00 · Fewer than 200 measured departures · 20 recorded · 20 measured · Source: the US BTS 11:00 · Fewer than 200 measured departures · 189 recorded · 189 measured · Source: the US BTS 12:00 · Fewer than 200 measured departures · 168 recorded · 168 measured · Source: the US BTS 13:00 · Fewer than 200 measured departures · 54 recorded · 54 measured · Source: the US BTS 14:00 · 8.8 min · 227 recorded · 224 measured · Source: the US BTS 15:00 · 11.6 min · 295 recorded · 295 measured · Source: the US BTS 16:00 · Fewer than 200 measured departures · 96 recorded · 93 measured · Source: the US BTS 17:00 · Fewer than 200 measured departures · 88 recorded · 88 measured · Source: the US BTS 18:00 · 9.2 min · 504 recorded · 502 measured · Source: the US BTS 19:00 · Fewer than 200 measured departures · 147 recorded · 145 measured · Source: the US BTS 20:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 21:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 22:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 23:00 · No observations · 0 recorded · 0 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Recorded flights Partial coverage: only airlines that report on-time data to the US DOT
00:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 01:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 02:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 03:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 04:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 05:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 06:00 · 274 · 274 recorded · 273 measured · Source: the US BTS 07:00 · 496 · 496 recorded · 491 measured · Source: the US BTS 08:00 · 303 · 303 recorded · 303 measured · Source: the US BTS 09:00 · 192 · 192 recorded · 191 measured · Source: the US BTS 10:00 · 20 · 20 recorded · 20 measured · Source: the US BTS 11:00 · 189 · 189 recorded · 189 measured · Source: the US BTS 12:00 · 168 · 168 recorded · 168 measured · Source: the US BTS 13:00 · 54 · 54 recorded · 54 measured · Source: the US BTS 14:00 · 227 · 227 recorded · 224 measured · Source: the US BTS 15:00 · 295 · 295 recorded · 295 measured · Source: the US BTS 16:00 · 96 · 96 recorded · 93 measured · Source: the US BTS 17:00 · 88 · 88 recorded · 88 measured · Source: the US BTS 18:00 · 504 · 504 recorded · 502 measured · Source: the US BTS 19:00 · 147 · 147 recorded · 145 measured · Source: the US BTS 20:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 21:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 22:00 · No observations · 0 recorded · 0 measured · Source: the US BTS 23:00 · No observations · 0 recorded · 0 measured · Source: the US BTS

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View the figures
Departure hourOn-time departuresAverage departure delayWith departure timeRecorded flights
00:00No observations———
01:00No observations———
02:00No observations———
03:00No observations———
04:00No observations———
05:00No observations———
06:0092.7%-0.5 min273274
07:0093.1%2.2 min491496
08:0088.5%3.2 min303303
09:00Fewer than 200 measured departures—191192
10:00Fewer than 200 measured departures—2020
11:00Fewer than 200 measured departures—189189
12:00Fewer than 200 measured departures—168168
13:00Fewer than 200 measured departures—5454
14:0082.6%8.8 min224227
15:0077.0%11.6 min295295
16:00Fewer than 200 measured departures—9396
17:00Fewer than 200 measured departures—8888
18:0077.1%9.2 min502504
19:00Fewer than 200 measured departures—145147
20:00No observations———
21:00No observations———
22:00No observations———
23:00No observations———

Day of week

On-time departures Partial coverage: only airlines that report on-time data to the US DOT
Monday · 81.0% · 466 recorded · 462 measured · Source: the US BTS Tuesday · 86.1% · 388 recorded · 387 measured · Source: the US BTS Wednesday · 85.0% · 392 recorded · 392 measured · Source: the US BTS Thursday · 77.2% · 470 recorded · 469 measured · Source: the US BTS Friday · 79.4% · 477 recorded · 475 measured · Source: the US BTS Saturday · 75.1% · 390 recorded · 386 measured · Source: the US BTS Sunday · 80.7% · 470 recorded · 465 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Average departure delay Partial coverage: only airlines that report on-time data to the US DOT
Monday · 7.9 min · 466 recorded · 462 measured · Source: the US BTS Tuesday · 5.4 min · 388 recorded · 387 measured · Source: the US BTS Wednesday · 5.0 min · 392 recorded · 392 measured · Source: the US BTS Thursday · 11.6 min · 470 recorded · 469 measured · Source: the US BTS Friday · 9.9 min · 477 recorded · 475 measured · Source: the US BTS Saturday · 9.8 min · 390 recorded · 386 measured · Source: the US BTS Sunday · 8.9 min · 470 recorded · 465 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Recorded flights Partial coverage: only airlines that report on-time data to the US DOT
Monday · 466 · 466 recorded · 462 measured · Source: the US BTS Tuesday · 388 · 388 recorded · 387 measured · Source: the US BTS Wednesday · 392 · 392 recorded · 392 measured · Source: the US BTS Thursday · 470 · 470 recorded · 469 measured · Source: the US BTS Friday · 477 · 477 recorded · 475 measured · Source: the US BTS Saturday · 390 · 390 recorded · 386 measured · Source: the US BTS Sunday · 470 · 470 recorded · 465 measured · Source: the US BTS

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View the figures
Day of weekOn-time departuresAverage departure delayWith departure timeRecorded flights
Monday81.0%7.9 min462466
Tuesday86.1%5.4 min387388
Wednesday85.0%5.0 min392392
Thursday77.2%11.6 min469470
Friday79.4%9.9 min475477
Saturday75.1%9.8 min386390
Sunday80.7%8.9 min465470

Month of year

Months combine the same calendar month across the years shown; this is a seasonal pattern, not a monthly time series.

On-time departures Partial coverage: only airlines that report on-time data to the US DOT
Jan · Fewer than 200 measured departures · 143 recorded · 139 measured · Source: the US BTS Feb · Fewer than 200 measured departures · 151 recorded · 151 measured · Source: the US BTS Mar · 89.3% · 209 recorded · 206 measured · Source: the US BTS Apr · 92.8% · 238 recorded · 236 measured · Source: the US BTS May · 78.6% · 320 recorded · 318 measured · Source: the US BTS Jun · 72.2% · 468 recorded · 467 measured · Source: the US BTS Jul · 74.4% · 492 recorded · 489 measured · Source: the US BTS Aug · 70.7% · 222 recorded · 222 measured · Source: the US BTS Sep · Fewer than 200 measured departures · 196 recorded · 196 measured · Source: the US BTS Oct · Fewer than 200 measured departures · 198 recorded · 198 measured · Source: the US BTS Nov · Fewer than 200 measured departures · 200 recorded · 199 measured · Source: the US BTS Dec · 84.7% · 216 recorded · 215 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Average departure delay Partial coverage: only airlines that report on-time data to the US DOT
Jan · Fewer than 200 measured departures · 143 recorded · 139 measured · Source: the US BTS Feb · Fewer than 200 measured departures · 151 recorded · 151 measured · Source: the US BTS Mar · 4.6 min · 209 recorded · 206 measured · Source: the US BTS Apr · 2.4 min · 238 recorded · 236 measured · Source: the US BTS May · 9.7 min · 320 recorded · 318 measured · Source: the US BTS Jun · 14.7 min · 468 recorded · 467 measured · Source: the US BTS Jul · 11.1 min · 492 recorded · 489 measured · Source: the US BTS Aug · 14.9 min · 222 recorded · 222 measured · Source: the US BTS Sep · Fewer than 200 measured departures · 196 recorded · 196 measured · Source: the US BTS Oct · Fewer than 200 measured departures · 198 recorded · 198 measured · Source: the US BTS Nov · Fewer than 200 measured departures · 200 recorded · 199 measured · Source: the US BTS Dec · 7.9 min · 216 recorded · 215 measured · Source: the US BTS

Hover, tap or focus a point to see its value, sample and source.

Recorded flights Partial coverage: only airlines that report on-time data to the US DOT
Jan · 143 · 143 recorded · 139 measured · Source: the US BTS Feb · 151 · 151 recorded · 151 measured · Source: the US BTS Mar · 209 · 209 recorded · 206 measured · Source: the US BTS Apr · 238 · 238 recorded · 236 measured · Source: the US BTS May · 320 · 320 recorded · 318 measured · Source: the US BTS Jun · 468 · 468 recorded · 467 measured · Source: the US BTS Jul · 492 · 492 recorded · 489 measured · Source: the US BTS Aug · 222 · 222 recorded · 222 measured · Source: the US BTS Sep · 196 · 196 recorded · 196 measured · Source: the US BTS Oct · 198 · 198 recorded · 198 measured · Source: the US BTS Nov · 200 · 200 recorded · 199 measured · Source: the US BTS Dec · 216 · 216 recorded · 215 measured · Source: the US BTS

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View the figures
Month of yearOn-time departuresAverage departure delayWith departure timeRecorded flights
JanFewer than 200 measured departures—139143
FebFewer than 200 measured departures—151151
Mar89.3%4.6 min206209
Apr92.8%2.4 min236238
May78.6%9.7 min318320
Jun72.2%14.7 min467468
Jul74.4%11.1 min489492
Aug70.7%14.9 min222222
SepFewer than 200 measured departures—196196
OctFewer than 200 measured departures—198198
NovFewer than 200 measured departures—199200
Dec84.7%7.9 min215216

Delay and on-time rates need at least 200 measured departures per bucket. Smaller samples remain visible in the flight-count chart. An empty slot means no observations, not zero flights.

Recorded outcomes

  • On time 80.1% 2,444
  • Delayed >15 min 19.4% 592
  • Cancelled 0.6% 17
  • Missing departure time 0.0% 0

All recorded flights with a known scheduled local time, counted once. Missing actual times are shown separately.

On time means departing no more than 15 minutes after schedule. Cancelled flights and flights missing departure times are excluded from the on-time rate and average delay.

Flight numbers on this route

19
19 of 19
Flight numbersBy direction DeparturesOn time
AS473 STL → SEA 511 93.5%
AS388 SEA → STL 475 86.7%
AS388 STL → SEA 383 77.6%
AS472 SEA → STL 306 77.8%
AS618 SEA → STL 145 90.3%
AS615 SEA → STL 133 86.4%
AS291 SEA → STL 113 62.0%
AS618 STL → SEA 111 79.1%
AS291 STL → SEA 94 54.8%
AS647 SEA → STL 80 82.5%
AS647 STL → SEA 79 75.6%
WN1242 SEA → STL 61 55.7%
AS504 STL → SEA 57 82.1%
WN3981 STL → SEA 57 57.9%
AS503 STL → SEA 52 69.2%
AS314 SEA → STL 48 89.6%
AS314 STL → SEA 46 88.6%
WN3632 SEA → STL 42 90.2%
AS503 SEA → STL 30 96.7%

Flight numbers are the codes sold on tickets. On shared flights one aircraft can carry several of them. Only numbers with at least 30 flights have a page.

Monthly figures
PeriodFlights operated Change vs last yearCancelled On-time departures
July 2026 244 −0.4% 2 80.7%
June 2026 236 +2.2% 0 81.4%
May 2026 162 +3.8% 0 79.0%
April 2026 118 +0.0% 2 96.6%
March 2026 102 −1.9% 3 91.2%
February 2026 75 −1.3% 0 93.3%
January 2026 73 +10.6% 2 80.8%
December 2025 107 −0.9% 1 76.6%
November 2025 99 −1.0% 1 86.9%
October 2025 122 +60.5% 0 84.4%
September 2025 196 0 80.6%
August 2025 222 0 70.7%
July 2025 245 1 68.2%
June 2025 231 1 62.8%
May 2025 156 2 78.2%
April 2025 118 0 89.0%
March 2025 104 0 87.5%
February 2025 76 0 89.5%
January 2025 66 2 83.3%
December 2024 108 0 92.6%
November 2024 100 0 83.0%
October 2024 76 0 90.8%

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