Route reliability record
SEA→HNL
Seattle to Honolulu
- Flights
- 2,938
- Period
- July 2025 to June 2026
- Distance
- 2,677 mi
- Carriers
- 3
This route draws a C+. About one flight in three arrive at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 2,938 flights, of which Delta Air Lines flew 789 at 77.9% on time.
Delta Air Lines is the most reliable of the three carriers covered here at 77.9% on time across 789 flights.
Key figures
On time
65.5%
Arrivals under 15 minutes late, of 2,896 completed flights
Avg delay
71 min
Across delayed arrivals only, not all flights
Cancelled
0.99%
National rate is 1.81%
Best carrier
Delta
77.9% on time across 789 flights
These figures cover 2,938 flights between July 2025 and June 2026. Beyond the headline rate, 9.2% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on SEA to HNL
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 77.9% of the time; Hawaiian Airlines manages 57.5%. Sample sizes sit next to every figure, because a two-point gap across 727 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 789 | 77.9% | 56 min | 0.76% | B+ |
| Alaska Airlines | 1,422 | 62.7% | 66 min | 0.84% | D+ |
| Hawaiian Airlines | 727 | 57.5% | 89 min | 1.51% | D |
The spread between Delta and Hawaiian is 20 points, wide enough that it should decide the booking. On a hundred trips that is 20 more arrivals inside the on-time window.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against 20 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am352 flights71.7%
- 8am–11am814 flights73.3%
- 11am–2pm472 flights60.8%
- 2pm–5pm621 flights64.4%
- 5pm–8pm513 flights63.3%
- 8pm–5am166 flights38.2%
Scale runs 30% to 80%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 38.2% on time, against 73.3% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 814 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 27 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.
July is the worst month at 50.4% on time, 27 points below October, the best at 77.6%. 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. March was the busiest month here, with 260 flights.
Across the week, Wednesday is the strongest day at 69.5% on time and Friday the weakest at 56.7%. 13 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 72% of the 71,000 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.
- 72%Carrier
- 16%Late-arriving aircraft
- 10%National Airspace System
- 1%Extreme weather
- 0%Security
The largest share of delay minutes, 72%, 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 51,000 of the 71,000 delay minutes reported here. The split is drawn from 71,293 reported delay minutes.
Cancellations sit at 0.99% against a national 1.81%, which is ordinary. Diversions add another 0.44%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.2% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 2,677 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 75.2% on time across 2,942 flights, 10 points above 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 10 points of difference.
The sample behind these figures is 2,938 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. October runs 77.6% on time and July 50.4%, a swing of 27 points. If the dates move at all, move them out of July before you think about anything else. 2,896 completed flights over 12 months sit behind that.
Common questions
SEA to HNL questions
How often is SEA to HNL delayed?
About one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 34.5% of the 2,938 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on SEA to HNL?
Delta Air Lines leads at 77.9% on time across 789 flights. Hawaiian Airlines is at the other end on 57.5%, a gap of 20 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 HNL?
The 8am–11am departure window is the strongest at 73.3% on time. The 8pm–5am window is the weakest at 38.2%, 35 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 SEA to HNL?
July is the weakest month at 50.4% on time, compared with 77.6% in October. Across the year that is 27 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- HNL to SEA — the return legseparate record
- Seattle-Tacoma International (SEA) delay statistics
- Daniel K. Inouye International (HNL) delay statistics
- Delta Air Lines on-time record77.9%
- Alaska Airlines on-time record62.7%
- Hawaiian Airlines on-time record57.5%
- The best time of day to fly, according to 7.04 million flight records
- Connecting flights: how much buffer the data says you need
Direction matters. SEA to HNL and HNL 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.