ON TIMEBOARD
SEA Seattle / PIT Pittsburgh

SEA → PIT on time

Seattle-Tacoma (Seattle, WA) to Pittsburgh (Pittsburgh, PA). Every scheduled flight, September 2025 to August 2026.

On time
78%
arrived < 15 min late
Cancelled
0.6%
474 flights
Typical arrival
−7 min
median vs schedule
When late
+42 min
average delay
Flights / day
1
1 airline

78% of flights from Seattle to Pittsburgh arrived on time over the past 12 months. That is about the typical U.S. route. The 10 a.m. departures ran on time 83% of the time; the 11 a.m. ones 77%. 5% 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 SEA → PIT: when a flight was late, it was under 45 minutes late 67% of the time. About 1 in 30 flights landed an hour or more late; 0.6% were cancelled outright.

Share of all 474 scheduled flights, past 12 months, by arrival time against schedule.

By airline

AirlineFlightsOn timeCancelledTypical arrival1h+ lateAvg when lateOperated by
Alaska Airlines47478%0.6%−7 min3.4%+42 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 SEA). Delays build through the day as late planes knock on, so early flights usually do best.

40%70%100%9 a.m. departures: too few flights (83 flights)9a10 a.m. departures: 83% on time (107 flights)8310a11 a.m. departures: 77% on time (149 flights)7711anoon 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 flights4p5 p.m. departures: too few flights5p6 p.m. departures: too few flights6p7 p.m. departures: too few flights7p8 p.m. departures: too few flights8p9 p.m. departures: too few flights (43 flights)9p10 p.m. departures: too few flights (68 flights)10p11 p.m. departures: too few flights (24 flights)11p
SEA → PIT, 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 SEA → PIT, each airline's last flight of the day was cancelled 0.0% of the time, against 0.0% for its earlier flights, about the same. It arrived 3+ hours late 0.0% of the time (earlier flights: 0.0%). 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 Airlines10:37 p.m.0.0%0.0%0.0%first flight 9:34 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.

By month

Each calendar month pooled over 2023–2026. Best: September (86%). Worst: August (68%).

40%70%100%Jan: too few flights (35 flights)JanFeb: too few flights (49 flights)FebMar: too few flights (85 flights)MarApr: too few flights (90 flights)AprMay: 74% on time (147 flights)74MayJun: 73% on time (180 flights)73JunJul: 70% on time (185 flights)70JulAug: 68% on time (174 flights)68AugSep: 86% on time (130 flights)86SepOct: too few flights (95 flights)OctNov: too few flights (84 flights)NovDec: too few flights (84 flights)Dec

By day of week

DayFlightsOn timeCancelled
Monday74——
Tuesday63——
Wednesday68——
Thursday72——
Friday73——
Saturday52——
Sunday72——

Why flights were late

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

Airline (crew, maintenance, ops) 48%Late inbound plane 33%Air traffic & airport (NAS) 13%Severe weather 5%

Cancellations: weather 2 · airline 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 4129:34 a.m.33679%0.9%−8 minAlaska Airlines

Questions

How often are flights from SEA to PIT on time?

78% of 474 scheduled flights from Seattle, WA to Pittsburgh, PA arrived within 15 minutes of schedule between September 2025 and August 2026. 0.6% were cancelled.

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

Flights scheduled to leave at 10 a.m. were the most reliable (83% on time). The 11 a.m. departures were the least (77%).

What month has the most delays from SEA to PIT?

August (68% on time). The best month is September (86%), over 2023–2026.

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

Not much. Each airline's last SEA–PIT flight of the day was cancelled 0.0% of the time over the past year, against 0.0% 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.