Route reliability record

SEA→SNA

Seattle to Santa Ana

Flights: 3,967
Period: July 2025 to June 2026
Distance: 978 mi
Carriers: 3

This route earns a A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 50 minutes. That rests on 3,967 flights, of which Alaska Airlines flew 2,608 at 86.3% on time.

Alaska Airlines is the most reliable of the three carriers covered here at 86.3% on time across 2,608 flights.

On time

85.1%

Arrivals under 15 minutes late, of 3,920 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

1.01%

National rate is 1.81%

Best carrier

Alaska

86.3% on time across 2,608 flights

These figures cover 3,967 flights between July 2025 and June 2026. The median arrival is 8 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

Which airline is most reliable on SEA to SNA

The three carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on SEA to SNA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Alaska Airlines	2,608	86.3%	39 min	1.15%	A
Delta Air Lines	954	83.0%	77 min	0.94%	B+
SkyWest Airlines	405	82.4%	36 min	0.25%	B+

No carrier stands out. Alaska tops the table at 86.3%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

The best time of day to leave

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 3,967 flights.

5am–8am705 flights89.8%
8am–11am514 flights84.3%
11am–2pm716 flights81.0%
2pm–5pm789 flights82.2%
5pm–8pm1,243 flights87.0%
8pm–5am—

Scale runs 75% to 95%. 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 81.0% on time against 89.8% 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. The 5pm–8pm window is the busiest, with 1,243 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 14 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

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

December is the weak month at 78.7% on time, against 92.9% in May. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 378 flights.

Across the week, Tuesday is the strongest day at 87.5% on time and Thursday the weakest at 82.5%. 5 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Carrier accounts for 57% of the 29,000 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.

Carrier
57%
Late-arriving aircraft
22%
National Airspace System
19%
Extreme weather
2%

The largest share of delay minutes, 57%, 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 16,000 of the 29,000 delay minutes reported here. The split is drawn from 28,637 reported delay minutes.

Cancellations sit at 1.01% against a national 1.81%, which is ordinary. Diversions add another 0.18%.

Connections and stage length

What a delay here actually costs

Badly late arrivals are rare here: only 3.0% 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 978 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 runs 85.7% on time across 3,965 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 3,967 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 this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 92.9% on time and December 78.7%, a swing of 14 points. If the dates move at all, move them out of December before you think about anything else. 3,920 completed flights over 12 months sit behind that.

Common questions

SEA to SNA questions

How often is SEA to SNA delayed?

About one flight in seven arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 14.9% of the 3,967 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 50 minutes on average.

Which airline is most reliable on SEA to SNA?

Alaska Airlines leads at 86.3% on time across 2,608 flights. SkyWest Airlines is at the other end on 82.4%, a gap of 4 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 SEA to SNA?

The 5am–8am departure window is the strongest at 89.8% on time. The 11am–2pm window is the weakest at 81.0%, 9 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 December delays on SEA to SNA?

December is the weakest month at 78.7% on time, compared with 92.9% in May. Across the year that is 14 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

Direction matters. SEA to SNA and SNA to SEA are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

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