ON TIMEBOARD

SAT → SEA on time

San Antonio (San Antonio, TX) to Seattle-Tacoma (Seattle, WA). Every scheduled flight, September 2025 to August 2026.

On time
78%
arrived < 15 min late
Cancelled
1.1%
550 flights
Typical arrival
−7 min
median vs schedule
When late
+57 min
average delay
Flights / day
2
1 airline

78% of flights from San Antonio to Seattle arrived on time over the past 12 months. That is about the typical U.S. route. The 6 a.m. departures ran on time 81% of the time; the 6 p.m. ones 72%. 7% of flights arrived more than an hour late or not at all.

How late?

The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for SAT → SEA: when a flight was late, it was under 45 minutes late 63% of the time. About 1 in 18 flights landed an hour or more late, and 1 in 92 three hours or more; 1.1% were cancelled outright.

Share of all 550 scheduled flights, past 12 months, by arrival time against schedule.

By airline

AirlineFlightsOn timeCancelledTypical arrival1h+ lateAvg when lateOperated by
Alaska Airlines55078%1.1%−7 min5.5%+57 minAlaska Airlines

Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.

Best time of day to fly

On-time rate by scheduled departure hour (local time at SAT). Delays build through the day as late planes knock on, so early flights usually do best.

40%70%100%6 a.m. departures: 81% on time (129 flights)816a7 a.m. departures: too few flights (98 flights)7a8 a.m. departures: too few flights8a9 a.m. departures: too few flights9a10 a.m. departures: too few flights10a11 a.m. departures: too few flights11anoon departures: too few flights12p1 p.m. departures: too few flights1p2 p.m. departures: too few flights2p3 p.m. departures: too few flights3p4 p.m. departures: too few flights (68 flights)4p5 p.m. departures: too few flights (77 flights)5p6 p.m. departures: 72% on time (136 flights)726p7 p.m. departures: too few flights (42 flights)7p
SAT → SEA, share of flights arriving on time, by departure hour. Hours with under 100 flights are greyed out.
82%+ on time76–82%68–76%under 68%too few flights

Last flight of the day

On SAT → SEA, each airline's last flight of the day was cancelled 1.6% of the time, against 1.1% for its earlier flights (1.5× as often). It arrived 3+ hours late 0.0% of the time (earlier flights: 2.2%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.

AirlineLast departureLast: cancelledLast: 3h+ lateEarlier: cancelledNext morning
Alaska Airlines4:44 p.m.1.6%0.0%1.1%first flight 7:02 a.m.

Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.

If you need to be in SEA tonight, book an earlier flight so there's a backup if it's cancelled.

By month

Each calendar month pooled over 2023–2026. Best: November (80%). Worst: June (67%).

40%70%100%Jan: 68% on time (105 flights)68JanFeb: too few flights (95 flights)FebMar: 71% on time (132 flights)71MarApr: 76% on time (145 flights)76AprMay: 76% on time (172 flights)76MayJun: 67% on time (180 flights)67JunJul: 68% on time (184 flights)68JulAug: 70% on time (162 flights)70AugSep: 79% on time (128 flights)79SepOct: 80% on time (133 flights)80OctNov: 80% on time (143 flights)80NovDec: 75% on time (167 flights)75Dec

By day of week

DayFlightsOn timeCancelled
Monday86——
Tuesday73——
Wednesday71——
Thursday83——
Friday83——
Saturday70——
Sunday84——

Why flights were late

Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.

Late inbound plane 46%Airline (crew, maintenance, ops) 35%Air traffic & airport (NAS) 15%Severe weather 4%

Cancellations: airline 5 · air traffic/airport 1

Month by month

Not enough months with data to draw a trend.

Flight numbers on this route

Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.

FlightDepartsFlightsOn timeCancelledTypical arrivalOperated by
AS 4944:44 p.m.28172%1.1%−3 minAlaska Airlines

Questions

How often are flights from SAT to SEA on time?

78% of 550 scheduled flights from San Antonio, TX to Seattle, WA arrived within 15 minutes of schedule between September 2025 and August 2026. 1.1% were cancelled.

What is the best time of day to fly SAT to SEA?

Flights scheduled to leave at 6 a.m. were the most reliable (81% on time). The 6 p.m. departures were the least (72%).

What month has the most delays from SAT to SEA?

June (67% on time). The best month is November (80%), over 2023–2026.

Is the last flight of the day from SAT to SEA more likely to be cancelled?

Yes. Each airline's last SAT–SEA flight of the day was cancelled 1.6% of the time over the past year, against 1.1% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.

Related

Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.