Flight number record

AS 389

Alaska Airlines · Boston to San Diego

Route: BOS → SAN
Departs: 17:45
Flights: 314
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s AS 389, check with Alaska Airlines.

AS 389 draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about 55 minutes behind schedule. Build slack into anything you connect to. That rests on 314 flights, with a median arrival 2 minutes late.

The national on-time rate over the same period is 77.6%, so AS 389 runs 14 points behind the country as a whole. Across a thousand flights that is about 140 extra late arrivals.

On time

63.6%

Arrivals under 15 minutes late, of 308 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

1.27%

National rate is 1.81%

1 hour+ late

10.4%

National rate is 8.1%

These figures cover 314 flights between July 2025 and June 2026. Beyond the headline rate, 10.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Schedule

When AS 389 flies

AS 389 flies BOS to SAN without a single fixed slot. Its most common scheduled departure was 17:45, used on 49 of 314 flights, with 16:24 (41 flights) and 17:40 (35 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 17:4549 flights15.6%
Departs 16:2441 flights13.1%
Departs 17:4035 flights11.1%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 17:45 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and AS 389 runs 5 points worse at 63.6%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

AS 389 next to BOS to SAN

Every carrier on BOS to SAN combined arrived on time 76.5% of the time across 1,818 flights, so AS 389 is 13 points behind it. Alaska flew 508 flights on the same city pair under all its flight numbers, including this one, and those ran 69.8% on time. Across its whole network Alaska Airlines managed 79.1%, which this flight trails by 15 points.

AS 389 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
AS 389thin sample	314	63.6%	55 min	1.27%	D
All Alaska Airlines on BOS–SAN	508	69.8%	56 min	1.57%	C
All carriers on BOS–SAN	1,818	76.5%	56 min	1.38%	B
Alaska Airlines, whole network	293,372	79.1%	52 min	1.28%	B

Across the year

AS 389 quarter by quarter

AS 389 did not run the same all year. Its best quarter was Jan–Mar 2026 at 71.6% on time and its weakest Jul–Sep 2025 at 45.2%, a swing of 26 points on roughly 79 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 202573 flights45.2%
Oct–Dec 202566 flights71.4%
Jan–Mar 202684 flights71.6%
Apr–Jun 202691 flights65.9%

Scale runs 35% to 75%. Rows with fewer than 30 flights show a dash.

By weekday, AS 389 did best on Saturday at 70.6% on time and worst on Friday at 56.2%. Each day rests on about 45 flights, so a gap of 14 points is worth noticing but could still narrow in another year.

Delay causes

Why AS 389 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 6,099 reported delay minutes.

National Airspace System
38%
Late-arriving aircraft
37%
Carrier
22%
Extreme weather
2%
Security
0%

37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 6,099 reported delay minutes here, that single category outweighs weather by 15 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 6,099 delay minutes reported on AS 389.

Cancellations sit at 1.27% against a national 1.81%, which is ordinary. Diversions add another 0.64%.

Connections and routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

At 2,588 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 314 flights under AS 389 in the data flew BOS to SAN. 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. 314 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 389

For a booking, AS 389 is one of the weaker ways to fly BOS to SAN: 13 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures