Flight number record
AS 1311
Alaska Airlines · San Jose to Seattle
- Route
- SJC → SEA
- Departs
- 10:19
- Flights
- 305
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s AS 1311, check with Alaska Airlines.
AS 1311 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.3%. When something does go wrong the average delay runs roughly 35 minutes. That rests on 305 flights, with a median arrival 13 minutes early.
Set against the rest of the country, AS 1311's record is 12 points better than the US average of 77.3%. That gap is worth roughly 123 fewer late arrivals for every thousand flights.
Key figures
On time
89.6%
Arrivals under 15 minutes late, of 299 completed flights
Avg delay
37 min
Across delayed arrivals only, not all flights
Cancelled
1.97%
National rate is 1.89%
1 hour+ late
1.7%
National rate is 8.3%
These figures cover 305 flights between September 2025 and August 2026. The median arrival is 13 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Schedule
When AS 1311 flies
AS 1311 flies SJC to SEA without a single fixed slot. Its most common scheduled departure was 10:19, used on 70 of 305 flights, with 11:00 (36 flights) and 10:24 (35 flights) next.
- Departs 10:1970 flights23.0%
- Departs 11:0036 flights11.8%
- Departs 10:2435 flights11.5%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 10:19 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and AS 1311 runs 6 points better at 89.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
AS 1311 next to SJC to SEA
Every carrier on SJC to SEA combined arrived on time 82.7% of the time across 4,422 flights, so AS 1311 is 7 points ahead of it. Alaska flew 1,884 flights on the same city pair under all its flight numbers, including this one, and those ran 80.7% on time. Across its whole network Alaska Airlines managed 79.7%, which this flight beats by 10 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| AS 1311thin sample | 305 | 89.6% | 37 min | 1.97% | A |
| All Alaska Airlines on SJC–SEA | 1,884 | 80.7% | 51 min | 1.27% | B |
| All carriers on SJC–SEA | 4,422 | 82.7% | 52 min | 0.61% | B+ |
| Alaska Airlines, whole network | 309,844 | 79.7% | 52 min | 1.20% | B |
Across the year
AS 1311 quarter by quarter
AS 1311 did not run the same all year. Its best quarter was Oct–Dec 2025 at 97.4% on time and its weakest Jul–Sep 2026 at 80.3%, a swing of 17 points on roughly 76 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202525 flights—
- Oct–Dec 202580 flights97.4%
- Jan–Mar 202681 flights91.1%
- Apr–Jun 202657 flights87.7%
- Jul–Sep 202662 flights80.3%
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, AS 1311 ranged from 84.8% on Thursday to 93.9% on Monday. With about 44 flights behind each day, a spread of 9 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late AS 1311 runs when it is late
AS 1311 often beats the schedule: 136 of 299 completed flights, 45%, arrived 15 minutes or more early. Most of the lateness is short. 18 of the 31 late arrivals were under half an hour behind, and 5 reached an hour or more.
- 15+ min early136 flights45.5%
- Within 15 min132 flights44.1%
- 15–29 min late18 flights6.0%
- 30–59 min late8 flights2.7%
- 1–2 hours late4 flights1.3%
- 2+ hours late1 flights0.3%
Scale runs 0% to 100%.
Share of 299 completed flights by arrival against schedule.
8 of 27 late departures made up the time and arrived on time, 30% of them. 12 flights left on time and still arrived late.
The worst days
Worst days for AS 1311
The latest arrival of the period was on 1 August 2026, 2 hours 9 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 1 August 2026 | 2 hours 9 minutes | Late-arriving aircraft |
| 21 September 2025 | 1 hour 50 minutes | Late-arriving aircraft |
| 22 July 2026 | 1 hour 18 minutes | Carrier |
| 25 March 2026 | 1 hour 13 minutes | Late-arriving aircraft |
| 16 July 2026 | 1 hour 10 minutes | National Airspace System |
Delay causes
Why AS 1311 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 1,135 reported delay minutes.
- 40%Late-arriving aircraft
- 39%National Airspace System
- 18%Carrier
- 2%Security
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 1,135 reported delay minutes here, that single category outweighs weather by 40 to one. The split is drawn from 1,135 delay minutes reported on AS 1311.
Cancellations sit at 1.97% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 1.7% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 696 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The same number turns up on one other city pair in the data, including GEG to LAX (28), but none flew often enough under AS 1311 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to SJC to SEA only.
One caution: this is a thin sample. 305 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking AS 1311
For a booking, read AS 1311 as 89.6% on time with 1.97% cancelled over 305 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SJC to SEA, every carrier and departure
- SEA to SJC, the return direction
- SkyWest Airlines 4041 on the same route95.1%
- SkyWest Airlines 3736 on the same route91.7%
- Norman Y. Mineta San Jose International (SJC) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Alaska Airlines on-time record
- Every Alaska Airlines flight number with a record
- The most and least reliable flight numbers in the US
- Why the first flight of the morning is statistically safest
A flight number here means Alaska Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.