Carrier route record

ASPHX→SEA

Alaska Airlines · Phoenix to Seattle

Flights: 2,903
Period: July 2025 to June 2026
Share of route: 40%
Carriers: 7

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

Alaska on PHX to SEA earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 2,903 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,764 at 87.8% on time.

Delta Air Lines is the most reliable of the four carriers covered here at 87.8% on time across 1,764 flights.

On time

84.9%

Arrivals under 15 minutes late, of 2,880 completed flights

Avg delay

56 min

Across delayed arrivals only, not all flights

Cancelled

0.76%

National rate is 1.81%

Whole route

82.7%

Every carrier on PHX to SEA, 7,269 flights

These figures cover 2,903 flights between July 2025 and June 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.

Carrier by carrier

Alaska against every carrier on PHX to SEA

Alaska flew 2,903 of the 7,269 flights on PHX to SEA, about 40% of it. Its 84.9% on time is 2 points better than the route as a whole, which runs 82.7%. Ranked by on-time rate it is number four of seven carriers on the route, where the range runs from Delta at 87.8% to Southwest at 64.8%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 87.8% of the time; Southwest Airlines manages 64.8%. Sample sizes sit next to every figure, because a two-point gap across 1,037 flights means less than a ten-point one.

On-time performance by carrier on PHX to SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	1,764	87.8%	73 min	0.85%	A+
Envoy Air	692	87.1%	45 min	0.00%	A+
Frontier Airlinesthin sample	165	86.1%	80 min	0.00%	A+
Alaska Airlines (this page)	2,903	84.9%	56 min	0.76%	B+
SkyWest Airlines	506	82.6%	61 min	0.59%	B+
American Airlinesthin sample	202	81.6%	53 min	0.50%	B+
Southwest Airlines	1,037	64.8%	43 min	0.58%	D+

The spread between Delta and Southwest is 23 points, wide enough that it should decide the booking. On a hundred trips that is 23 more arrivals inside the on-time window.

Flight by flight

Alaska flight numbers on PHX to SEA

Departure window

When Alaska runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 2,903 flights.

5am–8am616 flights87.7%
8am–11am532 flights83.4%
11am–2pm556 flights88.2%
2pm–5pm622 flights80.9%
5pm–8pm459 flights84.2%
8pm–5am118 flights84.3%

Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 88.2% on time, ahead of 2pm–5pm at 80.9%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 2pm–5pm window is the busiest, with 622 flights scheduled in it.

Across the year

Alaska on PHX to SEA through the year

Darker means more delays. Figures are on-time percentages.May best, August worst

August is the worst month at 76.1% on time, 17 points below May, the best at 93.4%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. April was the busiest month here, with 303 flights.

Across the week, Sunday is the strongest day at 88.0% on time and Friday the weakest at 82.0%. 6 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Alaska runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 24,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
48%
Carrier
29%
National Airspace System
19%
Extreme weather
4%
Security
0%

48% 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 24,000 reported delay minutes here, that single category outweighs weather by 11 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 24,185 reported delay minutes.

Cancellations are rare at 0.76%, below the national 1.81% 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 stage length

What a delay here costs

Badly late arrivals are rare here: only 3.2% land an hour or more behind schedule, against 8.1% 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 1,107 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 79.0% on time across 2,906 flights, 6 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 6 points of difference.

The sample behind these figures is 2,903 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking Alaska on PHX to SEA

Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 93.4% on time and August 76.1%, a swing of 17 points. If the dates move at all, move them out of August before you think about anything else. 2,880 completed flights over 12 months sit behind that.

Where to go next

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