Seattle/Tacoma International in September 2024

81.1%departed on time

BTS: A flight is counted as on time if it arrived less than 15 minutes after its scheduled time. Only carriers with at least 0.5 percent of domestic scheduled passenger revenue report.

In September 2024, reporting carriers scheduled 14,805 domestic departures from Seattle/Tacoma International (SEA). 81.1% left less than 15 minutes late and 78.1% reached their destination on time; 0.3% were cancelled.

Nationally that month, 84.4% of flights departed on time and 83.9% arrived on time, so SEA departures were 3.3 points below the national departure figure.

A year earlier, in September 2023, the airport had 15,041 departures with 82.6% leaving on time: a change of −1.5 points, with flights down 2%.

Flights arriving at SEA that month were on time 81.2% of the time (14,810 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, air carrier 44%, late-arriving aircraft 27% and national aviation system 24%.

On time 78.1%
Arrived 15+ minutes late 21.5%
Cancelled 0.3%
Diverted 0.1%

Every scheduled departure from SEA in September 2024, judged by arrival at the destination.

September 2024 against a year earlier, the airport's year and the nation

Measure	Sep 2024	Sep 2023	SEA, 12 months to Jul 2026	All reported flights, Sep 2024
Departed on time	81.1%	82.6%	78.2%	84.4%
Arrived on time	78.1%	80.8%	78.6%	83.9%
Cancelled	0.3%	0.4%	0.9%	0.6%
Average departure delay (late minutes only)	10.3 min	10.6 min	13.2 min	10.6 min
Scheduled departures a day	494	501	452	19,421
Scheduled departures	14,805	15,041	164,821	582,622

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
AS Alaska Airlines	7,222	49%	74.7%	6.1 min	0.5%
DL Delta Air Lines	2,762	19%	85.7%	-0.8 min	0.1%
OO SkyWest Airlines	2,217	15%	79.0%	5.0 min	0.1%
WN Southwest Airlines	849	6%	72.8%	8.2 min	0.2%
UA United Airlines	847	6%	86.0%	0.2 min	0.2%
AA American Airlines	493	3%	78.5%	1.5 min	0.6%
F9 Frontier Airlines	141	1%	70.2%	17.4 min	1.4%
NK Spirit Airlines	104	1%	82.7%	0.8 min	0.0%
B6 JetBlue Airways	63	0%	73.0%	2.7 min	0.0%
HA Hawaiian Airlines	60	0%	70.0%	27.7 min	1.7%
MQ Envoy Air	47	0%	91.5%	-9.5 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
SEA–ANC	Seattle to Anchorage	662	74.5%	4.5 min	0.5%
SEA–LAX	Seattle to Los Angeles	649	85.4%	-1.4 min	0.2%
SEA–SFO	Seattle to San Francisco	617	71.6%	7.8 min	0.8%
SEA–DEN	Seattle to Denver	606	80.5%	4.3 min	0.0%
SEA–LAS	Seattle to Las Vegas	579	76.7%	6.5 min	0.5%
SEA–PHX	Seattle to Phoenix	569	80.5%	1.1 min	0.0%
SEA–DFW	Seattle to Dallas/Fort Worth	484	71.9%	8.6 min	0.2%
SEA–ORD	Seattle to Chicago	483	78.7%	4.7 min	0.0%
SEA–PDX	Seattle to Portland	473	79.3%	4.9 min	0.0%
SEA–GEG	Seattle to Spokane	454	79.7%	5.2 min	0.0%
SEA–SJC	Seattle to San Jose	423	79.7%	3.5 min	1.2%
SEA–SAN	Seattle to San Diego	422	81.0%	1.3 min	0.5%

By scheduled departure hour

100

On-time share:under 62%6270768288% and over

Share of departures that left less than 15 minutes late, by scheduled hour (local time), September 2024.

Delay causes

BTS cause category	Share of delay minutes	National, Sep 2024	Minutes
Air carrier	44.2%	38.6%	63,325
Late-arriving aircraft	27.4%	38.4%	39,211
National Aviation System	24.1%	18.2%	34,498
Extreme weather	4.0%	4.8%	5,775
Security	0.3%	0.1%	485

143,294 delay minutes on 3,177 flights that arrived 15 or more minutes late and carried a cause report. Carriers assign the categories; see what each category means.

Questions and answers

How many flights left SEA on time in September 2024?

81.1% of 14,805 scheduled domestic departures left less than 15 minutes late, and 78.1% reached their destination on time. The national figures that month were 84.4% and 83.9%.

How does that compare with a year earlier?

In September 2023, 82.6% of 15,041 departures left on time and 0.4% were cancelled, against 81.1% and 0.3% in September 2024.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for September 2024; public domain. Domestic scheduled flights by reporting carriers, totals and averages only. The site's data runs through July 2026. Full record for SEA · methodology · corrections.