PlainFlights

Route · PHL → SEA · 2020–2025 BTS data

Philadelphia to Seattle

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), PHL to SEA (Philadelphia to Seattle) ranks #2268 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

76.5%
On-time
-2.5 pts
vs US avg
63 min
Delay when late
5,504
Flights
#2268 of 4927
Corpus placement

Cancelled

1.5%

Best Month

Feb 2024 93%

Worst Month

Dec 2025 39%

Distance

2,378 mi

Carriers

3

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 93 57 1 0 AS,AA
Nov 2025 87 19 0 0 AA,AS
Oct 2025 123 36 2 0 AA,AS
Sep 2025 122 24 0 0 AA,AS
Aug 2025 136 46 2 0 AA,AS
Jul 2025 123 51 4 1 AA,AS
Jun 2025 116 53 1 0 AA,AS
May 2025 92 32 0 0 AA,AS
Apr 2025 82 21 0 0 AA,AS
Mar 2025 71 11 0 0 AA,AS
Feb 2025 36 8 4 0 AA,AS
Jan 2025 39 13 0 0 AA,AS
Dec 2024 86 29 0 0 AA,AS
Nov 2024 74 13 0 0 AS,AA
Oct 2024 77 28 0 0 AS,AA
Sep 2024 92 32 0 1 AA,AS
Aug 2024 124 46 6 0 AA,AS
Jul 2024 123 44 2 1 AA,AS
Jun 2024 116 60 1 0 AA,AS
May 2024 93 29 1 0 AA,AS
Apr 2024 85 24 0 1 AA,AS
Mar 2024 72 14 0 0 AA,AS
Feb 2024 54 4 0 0 AA,AS
Jan 2024 59 16 8 0 AA,AS

PHL–SEA seasonal on-time pattern

Best: February (86.6%) · weakest: June (67.2%)

65%70%75%80%85%90% JanFebMarAprMayJunJulAugSepOctNovDec 68.3%

Strongest calendar month

February

86.6% on-time · ~51 flights/mo

Busiest calendar month

August

~116 flights/mo avg

Weakest calendar month

June

67.2% on-time · ~100 flights/mo

Cancellation Rate

1.5%

32 of 2,175 flights

Diversion Rate

0.2%

4 of 2,175 flights

Explore origin & destination

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

PHL - Philadelphia

Full on-time, delay-cause, and seasonal performance for Philadelphia, PA.

PHL 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 PHL and SEA side by side on delays, cancellations, and reliability.

Compare PHL vs SEA

Origin-hub reliability standing

Mid-pack among PHL departures

From PHL, this corridor sits with 60 other 75–85% on-time routes out of 65 tracked departures, not the hub's reliability leaders (4 at ≥85%) and not the softest ( 1 below 75%). Destination: Seattle · fleet on-time rank #4213 of 4927.

What the Data Says About PHL to SEA

The Philadelphia to Seattle corridor (PHL to SEA) posts a 76.5% on-time rate on the lower edge of the average band, based on 5,504 tracked flights. Late flights run 63.1 minutes behind on average. 3 carriers cover the 2,378-mile route; over the last 24 months, 32 of 2,175 flights were cancelled (1.5%) and 0.2% diverted.

The monthly split is wide on this route: Feb 2024 posted the strongest performance at 93% on-time, while Dec 2025 came in at just 39% - a 54-point swing worth factoring into travel timing.

On the multi-year calendar, PHL–SEA peaks in February at 86.6% on-time while August carries the heaviest traffic (~116 flights per month) ; the softest month is June at 67.2%, a 19.4-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does PHL to SEA rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, PHL to SEA ranks #2268 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 PHL to SEA? ▼
Flights from Philadelphia to Seattle have a 76.5% on-time rate based on 5,504 flights. The average delay is 63.1 minutes. The best recent month was Feb 2024 with 93% on-time.
What is the cancellation rate for PHL to SEA? ▼
Over the last 24 months, 1.5% of flights on this route were cancelled (32 of 2,175 flights) and 0.2% were diverted.
How far is the flight from PHL to SEA? ▼
The flight distance from Philadelphia (PHL) to Seattle (SEA) is approximately 2,378 miles. This route is served by 3 carriers.
When is the best time to fly from PHL to SEA? ▼
The best recent month for on-time performance was Feb 2024 (93% on-time). The worst was Dec 2025 (39% on-time). Consider booking during months with historically better performance.

Airports on this route

PHL Airport

Philadelphia
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 PHL–SEA data

PHL–SEA is mid-pack at 76.5% on-time; month and carrier mix move more than the corridor headline.

  • Compare PHL and SEA airport profiles: delay causes and top routes differ even on the same corridor. PHL airport
  • If your dates flex, February (86.6% on-time) beats June (67.2%) on this corridor. Seasonal chart
  • 4 other routes post a similar 76.5% 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.