Flight number record
AS 459
Alaska Airlines · Boston to Seattle
- Route
- BOS → SEA
- Departs
- 07:00
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s AS 459, check with Alaska Airlines.
AS 459 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 364 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.3%, so AS 459 runs 5 points behind the country as a whole. Across a thousand flights that is about 50 extra late arrivals.
Key figures
On time
72.3%
Arrivals under 15 minutes late, of 358 completed flights
Avg delay
44 min
Across delayed arrivals only, not all flights
Cancelled
0.82%
National rate is 1.89%
1 hour+ late
3.9%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Schedule
When AS 459 flies
AS 459 flies BOS to SEA without a single fixed slot. Its most common scheduled departure was 07:00, used on 133 of 364 flights, with 07:20 (83 flights) and 07:03 (69 flights) next.
- Departs 07:00133 flights36.5%
- Departs 07:2083 flights22.8%
- Departs 07:0369 flights19.0%
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 07:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and AS 459 runs 17 points worse at 72.3%. 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 459 next to BOS to SEA
Every carrier on BOS to SEA combined arrived on time 70.1% of the time across 2,555 flights, so AS 459 is 2 points ahead of it. Alaska flew 1,240 flights on the same city pair under all its flight numbers, including this one, and those ran 69.1% on time. Across its whole network Alaska Airlines managed 79.7%, which this flight trails by 7 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| AS 459thin sample | 364 | 72.3% | 44 min | 0.82% | C+ |
| All Alaska Airlines on BOS–SEA | 1,240 | 69.1% | 52 min | 1.37% | C |
| All carriers on BOS–SEA | 2,555 | 70.1% | 55 min | 1.49% | C |
| Alaska Airlines, whole network | 309,844 | 79.7% | 52 min | 1.20% | B |
Across the year
AS 459 quarter by quarter
AS 459 did not run the same all year. Its best quarter was Apr–Jun 2026 at 83.5% on time and its weakest Jan–Mar 2026 at 61.6%, a swing of 22 points on roughly 73 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 202530 flights83.3%
- Oct–Dec 202591 flights69.7%
- Jan–Mar 202690 flights61.6%
- Apr–Jun 202691 flights83.5%
- Jul–Sep 202662 flights69.4%
Scale runs 55% to 90%.
By weekday, AS 459 did best on Wednesday at 80.8% on time and worst on Thursday at 64.7%. Each day rests on about 52 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late AS 459 runs when it is late
AS 459 often beats the schedule: 101 of 358 completed flights, 28%, arrived 15 minutes or more early. The 99 late arrivals split 46 under half an hour, 39 between 30 and 60 minutes, and 14 an hour or more.
- 15+ min early101 flights28.2%
- Within 15 min158 flights44.1%
- 15–29 min late46 flights12.8%
- 30–59 min late39 flights10.9%
- 1–2 hours late8 flights2.2%
- 2+ hours late6 flights1.7%
Scale runs 0% to 100%.
Share of 358 completed flights by arrival against schedule.
6 of 46 late departures made up the time and arrived on time, 13% of them. In the other direction, 59 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SEA.
The worst days
Worst days for AS 459
The latest arrival of the period was on 19 April 2026, 5 hours 21 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 19 April 2026 | 5 hours 21 minutes | Carrier |
| 24 October 2025 | 2 hours 41 minutes | Carrier |
| 12 December 2025 | 2 hours 29 minutes | Carrier |
| 13 March 2026 | 2 hours 25 minutes | National Airspace System |
| 2 August 2026 | 2 hours 21 minutes | Carrier |
Delay causes
Why AS 459 runs late
National Airspace System accounts for 55% of the 4,305 delay minutes carriers reported here, and the remaining four split what is left.
- 55%National Airspace System
- 25%Carrier
- 16%Late-arriving aircraft
- 5%Extreme weather
55% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,349 minutes out of 4,305, against a national NAS share of 21%. The split is drawn from 4,305 delay minutes reported on AS 459.
Cancellations are rare at 0.82%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.9% 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.
At 2,496 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
Every one of the 364 flights under AS 459 in the data flew BOS to SEA. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 364 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 459
For a booking, read AS 459 as 72.3% on time with 0.82% cancelled over 364 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- BOS to SEA, every carrier and departure
- SEA to BOS, the return direction
- Delta Air Lines 384 on the same route74.3%
- Delta Air Lines 324 on the same route64.8%
- Boston Logan International (BOS) 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
- Worst months to fly in the US, ranked by the data
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.