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Route · SEA → IAD · 2020–2025 BTS data

Seattle to Washington

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), SEA to IAD (Seattle to Washington) ranks #1147 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

83.2%
On-time
+4.2 pts
vs US avg
65 min
Delay when late
10,099
Flights
#1147 of 4927
Corpus placement

Cancelled

1.2%

Best Month

Nov 2024 89%

Worst Month

Jul 2025 70%

Distance

2,306 mi

Carriers

8

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 124 15 0 0 DL,AS,UA
Nov 2025 119 18 0 1 UA,AS,DL
Oct 2025 155 23 2 0 AS,UA,DL
Sep 2025 179 22 0 1 UA,DL,AS
Aug 2025 222 62 1 0 UA,AS,DL
Jul 2025 245 74 1 2 AS,UA,DL
Jun 2025 240 55 3 3 AS,UA,DL
May 2025 203 50 2 1 AS,UA,DL
Apr 2025 155 29 0 0 UA,AS,DL
Mar 2025 116 20 0 0 AS,DL,UA
Feb 2025 94 18 0 1 AS,DL,UA
Jan 2025 103 20 2 0 AS,DL,UA
Dec 2024 135 19 0 1 AS,DL,UA
Nov 2024 180 20 0 0 UA,AS,DL
Oct 2024 194 22 0 0 UA,AS,DL
Sep 2024 231 35 2 0 UA,AS,DL
Aug 2024 264 44 3 6 AS,DL,UA
Jul 2024 278 58 8 0 AS,DL,UA
Jun 2024 270 50 1 1 AS,DL,UA
May 2024 228 51 2 0 AS,DL,UA
Apr 2024 147 25 0 0 AS,DL,UA
Mar 2024 119 33 0 0 AS,DL,UA
Feb 2024 96 14 0 0 AS,DL,UA
Jan 2024 104 21 24 0 AS,DL,UA

SEA–IAD seasonal on-time pattern

Best: February (87.7%) · weakest: June (78.1%)

75%80%85%90% JanFebMarAprMayJunJulAugSepOctNovDec 82.3%

Strongest calendar month

February

87.7% on-time · ~95 flights/mo

Busiest calendar month

August

~193 flights/mo avg

Weakest calendar month

June

78.1% on-time · ~173 flights/mo

Cancellation Rate

1.2%

51 of 4,201 flights

Diversion Rate

0.4%

17 of 4,201 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

IAD - Washington

Full on-time, delay-cause, and seasonal performance for Washington, DC.

IAD on-time profile

Compare the two airports

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

Compare SEA vs IAD

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: Washington · fleet on-time rank #1893 of 4927.

What the Data Says About SEA to IAD

Bureau of Transportation Statistics records show Seattle to Washington (SEA to IAD) running a 83.2% on-time rate over 10,099 tracked flights, on the stronger end of a typical domestic pairing. When flights do run late, the average delay is 64.9 minutes. The 2,306-mile corridor is served by 8 carriers, and over the last 24 months 1.2% of 4,201 flights were cancelled, 0.4% diverted.

The monthly split is wide on this route: Nov 2024 posted the strongest performance at 89% on-time, while Jul 2025 came in at just 70% - a 19-point swing worth factoring into travel timing.

On the multi-year calendar, SEA–IAD peaks in February at 87.7% on-time while August carries the heaviest traffic (~193 flights per month) ; the softest month is June at 78.1%, a 9.6-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does SEA to IAD rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, SEA to IAD ranks #1147 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 IAD? ▼
Flights from Seattle to Washington have a 83.2% on-time rate based on 10,099 flights. The average delay is 64.9 minutes. The best recent month was Nov 2024 with 89% on-time.
What is the cancellation rate for SEA to IAD? ▼
Over the last 24 months, 1.2% of flights on this route were cancelled (51 of 4,201 flights) and 0.4% were diverted.
How far is the flight from SEA to IAD? ▼
The flight distance from Seattle (SEA) to Washington (IAD) is approximately 2,306 miles. This route is served by 8 carriers.
When is the best time to fly from SEA to IAD? ▼
The best recent month for on-time performance was Nov 2024 (89% on-time). The worst was Jul 2025 (70% on-time). Consider booking during months with historically better performance.

Airports on this route

SEA Airport

Seattle
IAD Airport

Washington
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–IAD data

SEA–IAD runs 4.2 pts above the national 79% average; the remaining risk is month-to-month swing and carrier mix, not a weak headline rate.

  • Compare SEA and IAD airport profiles: delay causes and top routes differ even on the same corridor. SEA airport
  • If your dates flex, February (87.7% on-time) beats June (78.1%) on this corridor. Seasonal chart
  • 4 other routes post a similar 83.2% 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.