Carrier performance at one airport

AS→SEA

Alaska Airlines at Seattle-Tacoma International

Departures: 76,709
Period: June 2025 to May 2026
Routes: 25
Rank here: #6 of 10

Alaska Airlines at Seattle sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.4%. The late ones land roughly 45 minutes behind schedule. That rests on 76,709 flights, of which SkyWest Airlines flew 29,312 at 85.7% on time.

Measured against the airport rather than the country, Alaska Airlines runs 3 points behind the 78.7% weighted average across all carriers at SEA. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.

On time

75.8%

75,632 completed departures

Avg delay

47 min

Across delayed flights only

Cancelled

1.06%

At SEA, this carrier only

Rank here

Of 10 carriers clearing the floor at SEA

These figures cover 77,000 flights between June 2025 and May 2026. The median arrival is 3 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.

Against the competition

Every carrier at SEA, ranked

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 85.7% of the time; Hawaiian Airlines manages 59.9%. Sample sizes sit next to every figure, because a two-point gap across 1,222 flights means less than a ten-point one.

On-time performance of all carriers departing SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	29,312	85.7%	58 min	0.70%	A+
Envoy Air	646	84.9%	65 min	0.00%	B+
Delta Air Lines	32,222	81.5%	65 min	1.07%	B
United Airlines	8,807	80.7%	76 min	0.82%	B+
American Airlines	6,544	78.8%	87 min	2.17%	B
Alaska Airlines (this page)	76,709	75.8%	47 min	1.06%	B
Frontier Airlines	1,416	72.9%	90 min	2.26%	C
Southwest Airlines	8,101	70.8%	49 min	0.41%	C+
JetBlue Airways	414	60.7%	109 min	1.21%	D
Hawaiian Airlines	1,222	59.9%	80 min	1.06%	D

The spread between SkyWest and Hawaiian is 26 points, wide enough that it should decide the booking. On a hundred trips that is 26 more arrivals inside the on-time window.

Route by route

Where Alaska Airlines flies from SEA

Alaska Airlines operates 25 routes out of SEA with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.

Alaska Airlines routes from SEA
Route	Flights	On time	Avg delay	Cancelled	Grade
SEA to ANC · Anchorage	4,913	73.3%	47 min	1.14%	C
SEA to LAX · Los Angeles	3,285	79.9%	44 min	1.10%	B
SEA to PHX · Phoenix	2,930	77.9%	44 min	0.61%	B+
SEA to SAN · San Diego	2,788	75.3%	44 min	1.47%	B
SEA to SFO · San Francisco	2,744	62.1%	52 min	1.38%	D
SEA to LAS · Las Vegas	2,661	76.1%	45 min	0.98%	B+
SEA to SNA · Santa Ana	2,627	85.6%	39 min	1.18%	A
SEA to SJC · San Jose	1,891	79.9%	44 min	1.80%	B
SEA to FAI · Fairbanks	1,859	75.0%	43 min	0.75%	B+
SEA to GEG · Spokane	1,846	73.8%	42 min	0.81%	C+
SEA to ORD · Chicago	1,798	72.4%	52 min	0.89%	C+
SEA to DFW · Dallas-Fort Worth	1,755	77.0%	46 min	1.03%	B
SEA to DEN · Denver	1,571	74.0%	52 min	0.76%	C+
SEA to BUR · Burbank	1,568	79.6%	48 min	2.42%	B
SEA to JNU · Juneau	1,442	74.6%	47 min	1.46%	C
SEA to JFK · New York	1,403	67.3%	55 min	2.64%	C
SEA to SLC · Salt Lake City	1,355	78.3%	41 min	1.77%	B
SEA to HNL · Honolulu	1,305	62.0%	66 min	0.84%	D+
SEA to KTN · Ketchikan	1,301	75.4%	57 min	0.23%	B+
SEA to SMF · Sacramento	1,280	78.0%	45 min	0.62%	B+
SEA to ONT · Ontario	1,265	75.7%	47 min	1.90%	B
SEA to OGG · Kahului	1,230	75.3%	47 min	0.65%	B+
SEA to BOS · Boston	1,210	72.1%	49 min	0.99%	C+
SEA to EWR · Newark	1,208	80.8%	55 min	2.24%	B
SEA to AUS · Austin	1,125	76.0%	49 min	0.71%	B+

Departure window

Best time of day for this operation

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against 26 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am4,681 flights86.7%
8am–11am20,128 flights79.5%
11am–2pm14,815 flights72.1%
2pm–5pm9,714 flights74.5%
5pm–8pm11,910 flights73.0%
8pm–5am15,461 flights74.2%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 72.1% on time against 86.7% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise.

Across the year

Seasonal pattern

Darker means more delays. Figures are on-time percentages.April best, July worst

July is the worst month at 61.0% on time, 26 points below April, the best at 86.6%. 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.

Delay causes

What holds this operation up

Carrier
38%
Late-arriving aircraft
33%
National Airspace System
26%
Extreme weather
3%
Security
0%

The largest share of delay minutes, 38%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 323,000 of the 857,000 delay minutes reported here.

Cancellations sit at 1.06% against a national 1.80%, which is ordinary. Diversions add another 0.34%.

5.1% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the roughly 45 minutes kind, which a normal layover absorbs.

76,709 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 86.6% on time and July 61.0%, a swing of 26 points. If the dates move at all, move them out of July before you think about anything else.

Common questions

Alaska Airlines at SEA

How often is Alaska Airlines at SEA delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 24.2% of the 76,709 flights in this analysis, against 22.6% nationally. Delayed flights are late by roughly 45 minutes on average.

Which airline is most reliable on Alaska Airlines at SEA?

SkyWest Airlines leads at 85.7% on time across 29,312 flights. Hawaiian Airlines is at the other end on 59.9%, a gap of 26 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on Alaska Airlines at SEA?

The 5am–8am departure window is the strongest at 86.7% on time. The 11am–2pm window is the weakest at 72.1%, 15 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are July delays on Alaska Airlines at SEA?

July is the weakest month at 61.0% on time, compared with 86.6% in April. Across the year that is 26 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.

Key figures