ON TIMEBOARD

STS → SEA on time

Charles M. Schulz Sonoma (Santa Rosa, CA) to Seattle-Tacoma (Seattle, WA). Every scheduled flight, September 2025 to August 2026.

On time
76%
arrived < 15 min late
Cancelled
1.8%
684 flights
Typical arrival
−4 min
median vs schedule
When late
+50 min
average delay
Flights / day
2
1 airline

76% of flights from Santa Rosa to Seattle arrived on time over the past 12 months. That is about the typical U.S. route. The 11 a.m. departures ran on time 88% of the time; the 7 p.m. ones 52%. 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 STS → SEA: when a flight was late, it was under 45 minutes late 64% of the time. About 1 in 20 flights landed an hour or more late, and 1 in 342 three hours or more; 1.8% were cancelled outright.

Share of all 684 scheduled flights, past 12 months, by arrival time against schedule.

By airline

AirlineFlightsOn timeCancelledTypical arrival1h+ lateAvg when lateOperated by
Alaska Airlines68476%1.8%−4 min5.0%+50 minAlaska Airlines 52%, Horizon Air 34%, SkyWest 14%

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 STS). Delays build through the day as late planes knock on, so early flights usually do best.

40%70%100%6 a.m. departures: too few flights (20 flights)6a7 a.m. departures: too few flights (93 flights)7a8 a.m. departures: too few flights8a9 a.m. departures: too few flights9a10 a.m. departures: too few flights10a11 a.m. departures: 88% on time (105 flights)8811anoon departures: too few flights (70 flights)12p1 p.m. departures: too few flights (49 flights)1p2 p.m. departures: 71% on time (126 flights)712p3 p.m. departures: too few flights3p4 p.m. departures: too few flights4p5 p.m. departures: too few flights (16 flights)5p6 p.m. departures: too few flights (35 flights)6p7 p.m. departures: 52% on time (112 flights)527p8 p.m. departures: too few flights (38 flights)8p9 p.m. departures: too few flights (20 flights)9p
STS → 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 STS → SEA, each airline's last flight of the day was cancelled 2.5% of the time, against 1.3% for its earlier flights (2.0× as often). It arrived 3+ hours late 0.3% of the time (earlier flights: 0.3%). 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 Airlines7:23 p.m.2.5%0.3%1.3%first flight 12:52 p.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: October (86%). Worst: August (63%).

40%70%100%Jan: 77% on time (133 flights)77JanFeb: 82% on time (124 flights)82FebMar: 80% on time (142 flights)80MarApr: 74% on time (141 flights)74AprMay: 69% on time (170 flights)69MayJun: 67% on time (171 flights)67JunJul: 71% on time (182 flights)71JulAug: 63% on time (176 flights)63AugSep: 76% on time (204 flights)76SepOct: 86% on time (169 flights)86OctNov: 80% on time (165 flights)80NovDec: 63% on time (148 flights)63Dec

By day of week

DayFlightsOn timeCancelled
Monday10674%0.9%
Tuesday90——
Wednesday89——
Thursday10378%1.0%
Friday10373%4.9%
Saturday89——
Sunday10469%1.9%

Why flights were late

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

Late inbound plane 43%Airline (crew, maintenance, ops) 27%Air traffic & airport (NAS) 25%Severe weather 5%

Cancellations: weather 9 · airline 3

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 132212:52 p.m.20874%1.0%−3 minAlaska Airlines

Questions

How often are flights from STS to SEA on time?

76% of 684 scheduled flights from Santa Rosa, CA to Seattle, WA arrived within 15 minutes of schedule between September 2025 and August 2026. 1.8% were cancelled.

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

Flights scheduled to leave at 11 a.m. were the most reliable (88% on time). The 7 p.m. departures were the least (52%).

What month has the most delays from STS to SEA?

August (63% on time). The best month is October (86%), over 2023–2026.

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

Yes. Each airline's last STS–SEA flight of the day was cancelled 2.5% of the time over the past year, against 1.3% 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.