Carrier performance at one airport

AS→SEA

Alaska Airlines at Seattle-Tacoma International

Departures: 76,697
Period: July 2025 to June 2026
Routes: 25
Rank here: #6 of 10

Alaska Airlines at Seattle lands a B, level with the national rate of 77.6%. Roughly one flight in four arrive 15 minutes late or worse, and those flights are late by roughly 45 minutes on average. That is a workable record, not a spotless one. That rests on 76,697 flights, of which Envoy Air flew 691 at 86.9% on time.

Measured against the airport rather than the country, Alaska Airlines runs 2 points behind the 79.4% 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

77.2%

75,639 completed departures

Avg delay

47 min

Across delayed flights only

Cancelled

1.05%

At SEA, this carrier only

Rank here

Of 10 carriers clearing the floor at SEA

These figures cover 77,000 flights between July 2025 and June 2026. The median arrival is 4 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. Envoy Air arrives on time 86.9% of the time; JetBlue Airways manages 59.6%. Sample sizes sit next to every figure, because a two-point gap across 413 flights means less than a ten-point one.

On-time performance of all carriers departing SEA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Envoy Air	691	86.9%	71 min	0.00%	A+
SkyWest Airlines	29,109	86.1%	58 min	0.71%	A+
Delta Air Lines	32,257	81.5%	65 min	1.05%	B
United Airlines	8,804	80.2%	76 min	0.80%	B+
American Airlines	6,630	79.2%	97 min	2.07%	B
Alaska Airlines (this page)	76,697	77.2%	47 min	1.05%	B
Frontier Airlines	1,401	73.6%	90 min	2.28%	C
Southwest Airlines	8,105	70.0%	48 min	0.41%	C+
Hawaiian Airlines	1,034	60.5%	82 min	1.26%	D
JetBlue Airways	413	59.6%	109 min	0.73%	D+

The spread between Envoy and JetBlue is 27 points, wide enough that it should decide the booking. On a hundred trips that is 27 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	4,928	74.8%	47 min	1.12%	C
SEA to LAX · Los Angeles	3,282	81.0%	43 min	1.07%	B
SEA to PHX · Phoenix	2,906	79.0%	45 min	0.65%	B+
SEA to SAN · San Diego	2,765	75.0%	44 min	1.45%	B
SEA to SFO · San Francisco	2,716	60.3%	52 min	1.40%	D
SEA to LAS · Las Vegas	2,638	78.0%	47 min	0.91%	B+
SEA to SNA · Santa Ana	2,608	86.3%	39 min	1.15%	A
SEA to SJC · San Jose	1,877	80.6%	45 min	1.55%	B
SEA to FAI · Fairbanks	1,839	77.3%	44 min	0.71%	B+
SEA to GEG · Spokane	1,820	75.6%	43 min	0.82%	B+
SEA to ORD · Chicago	1,794	72.3%	55 min	1.06%	C
SEA to DFW · Dallas-Fort Worth	1,755	78.9%	44 min	1.03%	B
SEA to BUR · Burbank	1,590	80.1%	46 min	2.52%	B
SEA to DEN · Denver	1,558	75.9%	50 min	0.83%	B+
SEA to JNU · Juneau	1,448	76.3%	48 min	1.45%	B
SEA to HNL · Honolulu	1,422	62.7%	66 min	0.84%	D+
SEA to JFK · New York	1,403	71.6%	54 min	2.57%	C
SEA to SLC · Salt Lake City	1,372	79.6%	41 min	1.68%	B
SEA to SMF · Sacramento	1,310	79.8%	44 min	0.61%	B+
SEA to KTN · Ketchikan	1,303	76.9%	57 min	0.23%	B+
SEA to ONT · Ontario	1,268	77.4%	47 min	2.05%	B
SEA to OGG · Kahului	1,260	76.9%	47 min	0.63%	B+
SEA to EWR · Newark	1,238	81.0%	54 min	2.26%	B
SEA to BOS · Boston	1,207	73.7%	48 min	0.99%	C+
SEA to PDX · Portland	1,124	76.3%	41 min	1.33%	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 13 points, against 27 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am4,868 flights87.0%
8am–11am20,077 flights80.5%
11am–2pm14,827 flights74.2%
2pm–5pm9,638 flights76.0%
5pm–8pm11,952 flights73.8%
8pm–5am15,335 flights76.1%

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

Book the early departure. Flights leaving between 5am–8am arrive on time 87.0% of the time, against 73.8% for the evening window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 20,077 flights scheduled in it.

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. July was the busiest month here, with 7,510 flights.

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 310,000 of the 812,000 delay minutes reported here. The split is drawn from 811,699 reported delay minutes.

Cancellations sit at 1.05% against a national 1.81%, which is ordinary. Diversions add another 0.33%.

Badly late arrivals are rare here: only 4.9% 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.

76,697 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. 75,639 completed flights over 12 months sit behind that.

Common questions

Alaska Airlines at SEA

How often is Alaska Airlines at SEA delayed?

Roughly 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 22.8% of the 76,697 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 45 minutes on average.

Which airline is most reliable on Alaska Airlines at SEA?

Envoy Air leads at 86.9% on time across 691 flights. JetBlue Airways is at the other end on 59.6%, a gap of 27 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 87.0% on time. The 5pm–8pm window is the weakest at 73.8%, 13 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, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures