Seattle/Tacoma International in December 2023

83.4%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 December 2023, reporting carriers scheduled 12,736 domestic departures from Seattle/Tacoma International (SEA). 83.4% left less than 15 minutes late and 82.5% reached their destination on time; 0.5% were cancelled.

Nationally that month, 83.1% of flights departed on time and 83.8% arrived on time, so SEA departures were level with the national departure figure.

Flights arriving at SEA that month were on time 85.6% of the time (12,726 scheduled arrivals).

Of the delay minutes that carriers assigned to a BTS cause category that month, air carrier 42%, national aviation system 20% and late-arriving aircraft 19%.

On time 82.5%
Arrived 15+ minutes late 16.7%
Cancelled 0.5%
Diverted 0.3%

Every scheduled departure from SEA in December 2023, judged by arrival at the destination.

December 2023 against a year earlier, the airport's year and the nation

Measure	Dec 2023	Year earlier	SEA, 12 months to Jul 2026	All reported flights, Dec 2023
Departed on time	83.4%	—	78.2%	83.1%
Arrived on time	82.5%	—	78.6%	83.8%
Cancelled	0.5%	—	0.9%	0.4%
Average departure delay (late minutes only)	10.3 min	—	13.2 min	11.6 min
Scheduled departures a day	425	—	452	19,013
Scheduled departures	12,736	—	164,821	570,394

Airlines that month

Reporting carrier	Flights	Share	On time	Avg arrival delay	Cancelled
AS Alaska Airlines	6,222	49%	80.1%	1.4 min	0.4%
DL Delta Air Lines	2,621	21%	89.2%	-5.7 min	0.0%
OO SkyWest Airlines	1,842	14%	80.8%	9.7 min	2.2%
WN Southwest Airlines	660	5%	80.5%	3.3 min	0.3%
UA United Airlines	656	5%	85.1%	1.2 min	0.0%
AA American Airlines	454	4%	86.6%	-1.5 min	0.0%
F9 Frontier Airlines	94	1%	81.9%	-0.9 min	0.0%
NK Spirit Airlines	63	0%	87.3%	-3.3 min	0.0%
B6 JetBlue Airways	62	0%	56.5%	40.3 min	0.0%
HA Hawaiian Airlines	62	0%	72.6%	16.0 min	0.0%

Busiest routes that month

Route	Cities	Flights	On time	Avg arrival delay	Cancelled
SEA–PHX	Seattle to Phoenix	586	83.6%	3.0 min	0.2%
SEA–LAS	Seattle to Las Vegas	564	84.0%	-1.7 min	0.0%
SEA–ANC	Seattle to Anchorage	558	85.8%	-4.2 min	0.0%
SEA–LAX	Seattle to Los Angeles	556	83.8%	-1.7 min	0.2%
SEA–SFO	Seattle to San Francisco	546	76.6%	7.0 min	0.2%
SEA–DEN	Seattle to Denver	533	82.7%	1.7 min	0.4%
SEA–PDX	Seattle to Portland	458	78.2%	7.4 min	1.1%
SEA–GEG	Seattle to Spokane	407	78.1%	6.7 min	1.2%
SEA–SAN	Seattle to San Diego	383	87.5%	-3.7 min	0.3%
SEA–SJC	Seattle to San Jose	351	81.8%	1.3 min	0.6%
SEA–SNA	Seattle to Santa Ana	340	89.4%	-7.7 min	0.9%
SEA–SMF	Seattle to Sacramento	337	81.9%	4.8 min	0.6%

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), December 2023.

Delay causes

BTS cause category	Share of delay minutes	National, Dec 2023	Minutes
Air carrier	42.1%	37.1%	48,661
Late-arriving aircraft	19.4%	38.8%	22,383
National Aviation System	19.5%	17.6%	22,513
Extreme weather	18.9%	6.2%	21,815
Security	0.1%	0.3%	166

115,538 delay minutes on 2,133 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 December 2023?

83.4% of 12,736 scheduled domestic departures left less than 15 minutes late, and 82.5% reached their destination on time. The national figures that month were 83.1% and 83.8%.

How does that compare with a year earlier?

December 2022 is outside the 36 months on file, or the airport had too few reported flights that month.

Provenance

Source: Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, file for December 2023; 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.