Carrier performance at one airport

AS→SEA

Alaska Airlines at Seattle-Tacoma International

Departures: 76,970
Period: September 2025 to August 2026
Routes: 25
Rank here: #6 of 10

Alaska Airlines at Seattle lands a B+, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 45 minutes on average. That rests on 76,970 flights, of which Envoy Air flew 760 at 85.3% on time.

Measured against the airport rather than the country, Alaska Airlines runs about a point behind the 79.6% 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

78.5%

76,019 completed departures

Avg delay

47 min

Across delayed flights only

Cancelled

0.89%

At SEA, this carrier only

Rank here

Of 10 carriers clearing the floor at SEA

These figures cover 77,000 flights between September 2025 and August 2026. The median arrival is 5 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 85.3% of the time; JetBlue Airways manages 53.6%. 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	760	85.3%	74 min	0.00%	A+
SkyWest Airlines	28,580	84.9%	60 min	0.75%	B+
Delta Air Lines	32,382	80.7%	64 min	1.11%	B
United Airlines	8,683	79.9%	74 min	0.75%	B+
American Airlines	6,768	79.7%	97 min	1.73%	B
Alaska Airlines (this page)	76,970	78.5%	47 min	0.89%	B+
Frontier Airlines	1,397	75.8%	89 min	2.22%	B
Southwest Airlines	8,194	68.2%	50 min	0.44%	C+
Hawaiian Airlines	612	65.8%	93 min	1.47%	C
JetBlue Airways	413	53.6%	101 min	4.60%	F−

JetBlue Airways cancels 4.6% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

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	4,999	76.3%	47 min	0.74%	B+
SEA to LAX · Los Angeles	3,293	80.4%	42 min	0.91%	B+
SEA to PHX · Phoenix	2,889	79.2%	45 min	0.66%	B+
SEA to SAN · San Diego	2,728	73.3%	45 min	0.95%	C+
SEA to SFO · San Francisco	2,727	56.0%	52 min	1.14%	D
SEA to LAS · Las Vegas	2,612	78.7%	48 min	0.84%	B+
SEA to SNA · Santa Ana	2,570	86.3%	40 min	0.93%	A+
SEA to SJC · San Jose	1,887	79.8%	44 min	1.06%	B
SEA to FAI · Fairbanks	1,780	79.6%	43 min	0.39%	B+
SEA to ORD · Chicago	1,775	73.8%	59 min	1.13%	C
SEA to DFW · Dallas-Fort Worth	1,758	80.8%	43 min	0.85%	B+
SEA to GEG · Spokane	1,744	77.9%	43 min	0.52%	B+
SEA to HNL · Honolulu	1,659	61.7%	68 min	1.27%	D
SEA to BUR · Burbank	1,656	80.3%	46 min	2.17%	B
SEA to DEN · Denver	1,552	78.2%	48 min	0.64%	B+
SEA to JNU · Juneau	1,447	78.7%	51 min	1.24%	B
SEA to SLC · Salt Lake City	1,424	79.6%	40 min	1.26%	B
SEA to SMF · Sacramento	1,409	80.2%	44 min	0.57%	B+
SEA to JFK · New York	1,402	77.7%	53 min	2.64%	B
SEA to OGG · Kahului	1,322	78.2%	46 min	0.61%	B+
SEA to KTN · Ketchikan	1,315	78.4%	53 min	0.23%	B+
SEA to EWR · Newark	1,274	82.7%	54 min	2.28%	B
SEA to ONT · Ontario	1,257	77.5%	46 min	1.51%	B
SEA to BOS · Boston	1,240	77.5%	51 min	1.13%	B
SEA to PDX · Portland	1,202	76.7%	42 min	1.33%	B

Flight by flight

Alaska Airlines flight numbers from SEA

82 Alaska Airlines flight numbers leaving SEA flew their main route often enough to have a record of their own. Grouped by destination.

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 12 points, against 32 points between the best and worst carrier.

5am–8am5,488 flights87.4%
8am–11am19,876 flights81.3%
11am–2pm14,886 flights75.8%
2pm–5pm9,447 flights77.0%
5pm–8pm12,026 flights75.2%
8pm–5am15,247 flights77.6%

Scale runs 65% to 95%.

Book the early departure. Flights leaving between 5am–8am arrive on time 87.4% of the time, against 75.2% for the evening window. That is 12 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 19,876 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 70.1% on time, 17 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 7,592 flights.

Delay causes

What holds this operation up

Carrier
39%
Late-arriving aircraft
30%
National Airspace System
27%
Extreme weather
3%
Security
0%

The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 305,000 of the 774,000 delay minutes reported here. The split is drawn from 773,987 reported delay minutes.

Cancellations are rare at 0.89%, 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.

Badly late arrivals are rare here: only 4.6% 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.

76,970 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 70.1%, a swing of 17 points. If the dates move at all, move them out of July before you think about anything else. 76,019 completed flights over 12 months sit behind that.

Common questions

Alaska Airlines at SEA

How often is Alaska Airlines at SEA delayed?

About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.5% of the 76,970 flights in this analysis, against 22.7% 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 85.3% on time across 760 flights. JetBlue Airways is at the other end on 53.6%, a gap of 32 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 87.4% on time. The 5pm–8pm window is the weakest at 75.2%, 12 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 70.1% on time, compared with 86.6% in April. Across the year that is 17 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures