PlainFlights

Route · SEA → BWI · 2020–2025 BTS data

Seattle to Baltimore

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), SEA to BWI (Seattle to Baltimore) ranks #3470 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

81.6%
On-time
+2.6 pts
vs US avg
47 min
Delay when late
2,624
Flights
#3470 of 4927
Corpus placement

Cancelled

0.1%

Best Month

Sep 2023 95%

Worst Month

May 2025 55%

Distance

2,335 mi

Carriers

3

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 60 10 0 0 AS
Nov 2025 50 6 0 0 AS
Oct 2025 56 4 1 0 AS,WN
Sep 2025 90 17 0 0 WN,AS
Aug 2025 93 31 0 0 WN,AS
Jul 2025 92 28 0 2 AS,WN
Jun 2025 86 16 0 0 AS,WN
May 2025 58 26 0 1 AS
Apr 2025 37 12 0 0 AS
Mar 2025 31 6 0 0 AS
Dec 2024 54 8 0 0 AS
Nov 2024 50 4 0 0 AS
Oct 2024 52 9 0 0 AS
Sep 2024 59 18 0 0 AS
Aug 2024 63 12 0 1 AS,WN
Jul 2024 66 21 0 0 AS,WN
Jun 2024 64 14 0 0 AS,WN
May 2024 62 15 0 0 AS
Apr 2024 45 8 0 0 AS
Mar 2024 31 15 0 0 AS
Dec 2023 31 6 0 0 AS
Nov 2023 30 6 0 0 AS
Oct 2023 31 6 0 0 AS
Sep 2023 60 3 0 1 AS

SEA–BWI seasonal on-time pattern

Best: November (87.7%) · weakest: May (72.5%)

70%75%80%85%90% JanMarAprMayJunJulAugSepOctNovDec 84.5%

Strongest calendar month

November

87.7% on-time · ~43 flights/mo

Busiest calendar month

July

~69 flights/mo avg

Weakest calendar month

May

72.5% on-time · ~46 flights/mo

Cancellation Rate

0.1%

1 of 1,351 flights

Diversion Rate

0.4%

5 of 1,351 flights

Explore origin & destination

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

SEA - Seattle

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

SEA on-time profile

BWI - Baltimore

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

BWI on-time profile

Compare the two airports

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

Compare SEA vs BWI

Origin-hub reliability standing

Mid-pack among SEA departures

From SEA, this corridor sits with 63 other 75–85% on-time routes out of 89 tracked departures, not the hub's reliability leaders (25 at ≥85%) and not the softest ( 1 below 75%). Destination: Baltimore · fleet on-time rank #2527 of 4927.

What the Data Says About SEA to BWI

2,624 tracked flights put the SEA to BWI pairing (Seattle to Baltimore) at a 81.6% on-time rate, squarely in line with the wider network. Delays that do occur run 47.3 minutes on average. Across the 2,335-mile route and its 3 carriers, the trailing 24 months show 0.1% cancelled and 0.4% diverted (1,351 flights sampled).

The monthly split is wide on this route: Sep 2023 posted the strongest performance at 95% on-time, while May 2025 came in at just 55% - a 40-point swing worth factoring into travel timing.

On the multi-year calendar, SEA–BWI peaks in November at 87.7% on-time while July carries the heaviest traffic (~69 flights per month) ; the softest month is May at 72.5%, a 15.2-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does SEA to BWI rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, SEA to BWI ranks #3470 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 SEA to BWI? ▼
Flights from Seattle to Baltimore have a 81.6% on-time rate based on 2,624 flights. The average delay is 47.3 minutes. The best recent month was Sep 2023 with 95% on-time.
What is the cancellation rate for SEA to BWI? ▼
Over the last 24 months, 0.1% of flights on this route were cancelled (1 of 1,351 flights) and 0.4% were diverted.
How far is the flight from SEA to BWI? ▼
The flight distance from Seattle (SEA) to Baltimore (BWI) is approximately 2,335 miles. This route is served by 3 carriers.
When is the best time to fly from SEA to BWI? ▼
The best recent month for on-time performance was Sep 2023 (95% on-time). The worst was May 2025 (55% on-time). Consider booking during months with historically better performance.

Airports on this route

SEA Airport

Seattle
BWI Airport

Baltimore
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 SEA–BWI data

SEA–BWI is mid-pack at 81.6% on-time; month and carrier mix move more than the corridor headline.

  • Compare SEA and BWI airport profiles: delay causes and top routes differ even on the same corridor. SEA airport
  • If your dates flex, November (87.7% on-time) beats May (72.5%) on this corridor. Seasonal chart
  • 4 other routes post a similar 81.6% 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.