Flight number record
AS 358
Alaska Airlines · Portland to Boston
- Route
- PDX → BOS
- Departs
- 07:00
- Flights
- 349
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s AS 358, check with Alaska Airlines.
AS 358 lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That rests on 349 flights, with a median arrival 7 minutes early.
Set against the rest of the country, AS 358's record is 6 points better than the US average of 77.3%. That gap is worth roughly 62 fewer late arrivals for every thousand flights.
Key figures
On time
83.5%
Arrivals under 15 minutes late, of 345 completed flights
Avg delay
44 min
Across delayed arrivals only, not all flights
Cancelled
0.86%
National rate is 1.89%
1 hour+ late
2.6%
National rate is 8.3%
These figures cover 349 flights between September 2025 and August 2026. The median arrival is 7 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 358 flies
AS 358 flies PDX to BOS without a single fixed slot. Its most common scheduled departure was 07:00, used on 184 of 349 flights.
- Departs 07:00184 flights52.7%
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 358 runs 6 points worse at 83.5%. 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 358 next to PDX to BOS
Every carrier on PDX to BOS combined arrived on time 78.5% of the time across 699 flights, so AS 358 is 5 points ahead of it. Alaska flew 538 flights on the same city pair under all its flight numbers, including this one, and those ran 82.7% on time. Across its whole network Alaska Airlines managed 79.7%, which this flight beats by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| AS 358thin sample | 349 | 83.5% | 44 min | 0.86% | B+ |
| All Alaska Airlines on PDX–BOS | 538 | 82.7% | 41 min | 0.74% | B+ |
| All carriers on PDX–BOS | 699 | 78.5% | 62 min | 1.86% | B |
| Alaska Airlines, whole network | 309,844 | 79.7% | 52 min | 1.20% | B |
Across the year
AS 358 quarter by quarter
AS 358 did not run the same all year. Its best quarter was Jan–Mar 2026 at 93.1% on time and its weakest Jul–Sep 2025 at 70.0%, a swing of 23 points on roughly 70 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 flights70.0%
- Oct–Dec 202591 flights77.8%
- Jan–Mar 202675 flights93.1%
- Apr–Jun 202691 flights81.3%
- Jul–Sep 202662 flights90.3%
Scale runs 60% to 100%.
By weekday, AS 358 did best on Sunday at 92.2% on time and worst on Tuesday at 72.3%. Each day rests on about 50 flights, so a gap of 20 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late AS 358 runs when it is late
AS 358 often beats the schedule: 114 of 345 completed flights, 33%, arrived 15 minutes or more early. The 57 late arrivals split 25 under half an hour, 23 between 30 and 60 minutes, and 9 an hour or more.
- 15+ min early114 flights33.0%
- Within 15 min174 flights50.4%
- 15–29 min late25 flights7.2%
- 30–59 min late23 flights6.7%
- 1–2 hours late6 flights1.7%
- 2+ hours late3 flights0.9%
Scale runs 0% to 100%.
Share of 345 completed flights by arrival against schedule.
16 of 55 late departures made up the time and arrived on time, 29% of them. In the other direction, 18 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 BOS.
The worst days
Worst days for AS 358
The latest arrival of the period was on 25 August 2026, 3 hours 35 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On three of the five worst days the largest share was filed as national airspace system delay.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 25 August 2026 | 3 hours 35 minutes | Carrier |
| 30 July 2026 | 2 hours 43 minutes | Carrier |
| 14 October 2025 | 2 hours 2 minutes | National Airspace System |
| 15 May 2026 | 1 hour 44 minutes | National Airspace System |
| 14 May 2026 | 1 hour 39 minutes | National Airspace System |
Delay causes
Why AS 358 runs late
National Airspace System accounts for 62% of the 2,518 delay minutes carriers reported here, and the remaining four split what is left.
- 62%National Airspace System
- 37%Carrier
- 1%Late-arriving aircraft
62% 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 1,559 minutes out of 2,518, against a national NAS share of 21%. The split is drawn from 2,518 delay minutes reported on AS 358.
Cancellations are rare at 0.86%, 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 2.6% 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 2,537 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 349 flights under AS 358 in the data flew PDX to BOS. 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. 349 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 358
For a booking, read AS 358 as 83.5% on time with 0.86% cancelled over 349 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- Portland International (PDX) delay statistics
- Boston Logan International (BOS) 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.