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Route · SEA → SFO · 2020–2025 BTS data

Seattle to San Francisco

According to PlainFlights' route traffic ranking (BTS On-Time Performance total flights), SEA to SFO (Seattle to San Francisco) ranks #44 of 4927 tracked domestic routes by total flights (most flights = #1).

Data updated 2026-06-13

79.1%
On-time
+0.1 pts
vs US avg
62 min
Delay when late
37,651
Flights
#44 of 4927
Corpus placement

Cancelled

1.1%

Best Month

Jan 2025 87%

Worst Month

Apr 2024 50%

Distance

679 mi

Carriers

26

Monthly Performance

Recent 24 months of route data.

Period Flights Delayed Cancelled Diverted Carriers
Dec 2025 558 188 4 0 DL,AS,UA,OO
Nov 2025 567 154 13 1 OO,UA,DL,AS
Oct 2025 584 156 7 0 AS,OO,UA,DL
Sep 2025 584 144 4 0 UA,OO,DL,AS
Aug 2025 619 160 4 2 OO,UA,AS,DL
Jul 2025 639 184 12 0 AS,DL,OO,UA
Jun 2025 630 176 4 0 AS,DL,OO,UA
May 2025 636 146 3 0 AS,DL,OO,UA
Apr 2025 539 116 2 0 DL,OO,UA,AS
Mar 2025 560 148 3 0 AS,DL,OO,UA
Feb 2025 484 137 10 1 AS,DL,OO,UA
Jan 2025 523 67 2 0 AS,DL,OO,UA
Dec 2024 532 145 2 0 AS,DL,OO,UA
Nov 2024 548 124 6 0 OO,UA,AS,DL
Oct 2024 611 119 3 0 UA,AS,OO,DL
Sep 2024 617 170 5 0 OO,UA,AS,DL
Aug 2024 627 216 8 1 AS,DL,OO,UA
Jul 2024 624 152 18 0 AS,DL,OO,UA
Jun 2024 523 199 3 0 AS,DL,OO,UA
May 2024 545 244 3 0 AS,DL,OO,UA
Apr 2024 517 258 1 0 AS,DL,OO,UA
Mar 2024 523 245 0 0 AS,DL,OO,UA
Feb 2024 445 187 5 0 AS,DL,OO,UA
Jan 2024 487 128 32 0 AS,DL,OO,UA

SEA–SFO seasonal on-time pattern

Best: October (82.9%) · weakest: December (73.2%)

70%75%80%85% JanFebMarAprMayJunJulAugSepOctNovDec 73.2%

Strongest calendar month

October

82.9% on-time · ~560 flights/mo

Busiest calendar month

August

~569 flights/mo avg

Weakest calendar month

December

73.2% on-time · ~507 flights/mo

Cancellation Rate

1.1%

154 of 13,522 flights

Diversion Rate

0.0%

5 of 13,522 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

SFO - San Francisco

Full on-time, delay-cause, and seasonal performance for San Francisco, CA.

SFO on-time profile

Compare the two airports

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

Compare SEA vs SFO

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: San Francisco · fleet on-time rank #3497 of 4927.

What the Data Says About SEA to SFO

37,651 tracked flights put the SEA to SFO pairing (Seattle to San Francisco) at a 79.1% on-time rate, squarely in line with the wider network. Delays that do occur run 61.9 minutes on average. Across the 679-mile route and its 26 carriers, the trailing 24 months show 1.1% cancelled and 0.0% diverted (13,522 flights sampled).

The monthly split is wide on this route: Jan 2025 posted the strongest performance at 87% on-time, while Apr 2024 came in at just 50% - a 37-point swing worth factoring into travel timing.

On the multi-year calendar, SEA–SFO peaks in October at 82.9% on-time while August carries the heaviest traffic (~569 flights per month) ; the softest month is December at 73.2%, a 9.7-point swing that repeats because the corridor's weather and holiday mix stays stable year to year.

Frequently Asked Questions

Where does SEA to SFO rank among US routes by traffic? ▼
According to PlainFlights' route traffic ranking, SEA to SFO ranks #44 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 SFO? ▼
Flights from Seattle to San Francisco have a 79.1% on-time rate based on 37,651 flights. The average delay is 61.9 minutes. The best recent month was Jan 2025 with 87% on-time.
What is the cancellation rate for SEA to SFO? ▼
Over the last 24 months, 1.1% of flights on this route were cancelled (154 of 13,522 flights) and 0.0% were diverted.
How far is the flight from SEA to SFO? ▼
The flight distance from Seattle (SEA) to San Francisco (SFO) is approximately 679 miles. This route is served by 26 carriers.
When is the best time to fly from SEA to SFO? ▼
The best recent month for on-time performance was Jan 2025 (87% on-time). The worst was Apr 2024 (50% on-time). Consider booking during months with historically better performance.

Airports on this route

SEA Airport

Seattle
SFO Airport

San Francisco
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–SFO data

SEA–SFO is mid-pack at 79.1% on-time; month and carrier mix move more than the corridor headline.

  • Compare SEA and SFO airport profiles: delay causes and top routes differ even on the same corridor. SEA airport
  • If your dates flex, October (82.9% on-time) beats December (73.2%) on this corridor. Seasonal chart
  • 4 other routes post a similar 79.1% 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.