PlainFlights

Route · BWI → SEA · 2020–2025 BTS data

Baltimore to Seattle

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), BWI to SEA (Baltimore to Seattle) ranks #3471 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

73.8%
On-time
-5.2 pts
vs US avg
56 min
Delay when late
2,623
Flights
#3471 of 4927
Corpus placement

Cancelled

0.7%

Best Month

Oct 2025 89%

Worst Month

Dec 2025 33%

Distance

2,335 mi

Carriers

3

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 60 40 1 0 AS
Nov 2025 50 11 0 0 AS
Oct 2025 56 6 1 0 AS,WN
Sep 2025 90 13 0 0 WN,AS
Aug 2025 93 17 1 0 WN,AS
Jul 2025 92 43 0 1 AS,WN
Jun 2025 86 35 0 0 AS,WN
May 2025 58 23 0 0 AS
Apr 2025 36 17 1 0 AS
Mar 2025 31 8 0 0 AS
Dec 2024 54 12 0 0 AS
Nov 2024 50 10 0 0 AS
Oct 2024 52 7 0 0 AS
Sep 2024 59 24 1 0 AS
Aug 2024 63 18 0 1 AS,WN
Jul 2024 66 21 0 0 AS,WN
Jun 2024 64 41 1 0 AS,WN
May 2024 62 20 0 0 AS
Apr 2024 44 14 0 0 AS
Mar 2024 31 13 1 0 AS
Dec 2023 31 6 1 0 AS
Nov 2023 30 9 0 0 AS
Oct 2023 32 7 0 0 AS
Sep 2023 60 9 1 0 AS

BWI–SEA seasonal on-time pattern

Best: January (82.8%) · weakest: June (59.0%)

50%60%70%80%90% JanMarAprMayJunJulAugSepOctNovDec 66%

Strongest calendar month

January

82.8% on-time · ~32 flights/mo

Busiest calendar month

July

~69 flights/mo avg

Weakest calendar month

June

59.0% on-time · ~57 flights/mo

Cancellation Rate

0.7%

9 of 1,350 flights

Diversion Rate

0.1%

2 of 1,350 flights

Explore origin & destination

On-time and delay data for the airports this route connects.

BWI - Baltimore

Full on-time, delay-cause, and seasonal performance for Baltimore, MD.

BWI on-time profile

SEA - Seattle

Full on-time, delay-cause, and seasonal performance for Seattle, WA.

SEA on-time profile

Compare the two airports

See BWI and SEA side by side on delays, cancellations, and reliability.

Compare BWI vs SEA

Origin-hub reliability standing

Softer reliability from BWI

Among 64 routes leaving BWI, only 11 (including this one) clear below 75% on-time, while 0 stay ≥85% and 53 sit mid-band. Travelers comparing BWI options should weigh this 73.8% print against those peers · fleet on-time rank #4615 of 4927.

What the Data Says About BWI to SEA

On-time performance on the BWI to SEA pairing (Baltimore to Seattle) trails a chunk of the network: 73.8% of 2,623 tracked flights arrived on schedule, with a 56.4-minute average delay on the ones that ran late. The route spans about 2,335 miles across 3 carriers. Cancellations over the trailing 24 months hit 0.7% (9 of 1,350 flights), with 0.1% diverted.

The monthly split is wide on this route: Oct 2025 posted the strongest performance at 89% on-time, while Dec 2025 came in at just 33% - a 56-point swing worth factoring into travel timing.

On the multi-year calendar, BWI–SEA peaks in January at 82.8% on-time while July carries the heaviest traffic (~69 flights per month) ; the softest month is June at 59.0%, a 23.8-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does BWI to SEA rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, BWI to SEA ranks #3471 of 4927 tracked domestic routes by total flights (most flights = #1). That ordinal matches our busiest-routes listing (total_flights DESC). See /methodology#corpus-placement for the exact sort basis.
How often are flights delayed from BWI to SEA? ▼
Flights from Baltimore to Seattle have a 73.8% on-time rate based on 2,623 flights. The average delay is 56.4 minutes. The best recent month was Oct 2025 with 89% on-time.
What is the cancellation rate for BWI to SEA? ▼
Over the last 24 months, 0.7% of flights on this route were cancelled (9 of 1,350 flights) and 0.1% were diverted.
How far is the flight from BWI to SEA? ▼
The flight distance from Baltimore (BWI) to Seattle (SEA) is approximately 2,335 miles. This route is served by 3 carriers.
When is the best time to fly from BWI to SEA? ▼
The best recent month for on-time performance was Oct 2025 (89% on-time). The worst was Dec 2025 (33% on-time). Consider booking during months with historically better performance.

Airports on this route

BWI Airport

Baltimore
SEA Airport

Seattle
Data source

Data Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data. Statistics reflect cumulative performance across all available reporting periods.

Read our methodology - how this data is sourced, computed, and verified.

Using BWI–SEA data

BWI–SEA sits 5.2 pts below the national 79% average; check the seasonal chart and airport profiles before treating the headline as typical.

  • Compare BWI and SEA airport profiles: delay causes and top routes differ even on the same corridor. BWI airport
  • If your dates flex, January (82.8% on-time) beats June (59.0%) on this corridor. Seasonal chart
  • 4 other routes post a similar 73.8% on-time rate; compare before you commit to this pairing. Similar routes

On-time rate reflects the BTS historical average across all reporting carriers on this origin–destination pair, not any single flight or booking recommendation.

Data sourced from U.S. Department of Transportation Bureau of Transportation Statistics (BTS) On-Time Performance data. See our methodology for details. Retrieved and formatted by PlainFlights

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This page aggregates this specific route's on-time performance and monthly trend, live from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.