Flight number record
DL 351
Delta Air Lines · Seattle to Honolulu
- Route
- SEA → HNL
- Departs
- 08:25
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 351, check with Delta Air Lines.
DL 351 lands a B+, 6 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That rests on 365 flights, with a median arrival 6 minutes early.
Set against the rest of the country, DL 351's record is 6 points better than the US average of 77.3%. That gap is worth roughly 63 fewer late arrivals for every thousand flights.
Key figures
On time
83.6%
Arrivals under 15 minutes late, of 359 completed flights
Avg delay
42 min
Across delayed arrivals only, not all flights
Cancelled
0.27%
National rate is 1.89%
1 hour+ late
2.8%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. The median arrival is 6 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.
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Schedule
When DL 351 flies
DL 351 flies SEA to HNL without a single fixed slot. Its most common scheduled departure was 08:25, used on 72 of 365 flights, with 08:45 (69 flights) and 08:35 (41 flights) next.
- Departs 08:2572 flights19.7%
- Departs 08:4569 flights18.9%
- Departs 08:3541 flights11.2%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 08:25 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 83.9%, and DL 351 runs level with that at 83.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 351 next to SEA to HNL
Every carrier on SEA to HNL combined arrived on time 66.2% of the time across 2,927 flights, so DL 351 is 17 points ahead of it. Delta flew 789 flights on the same city pair under all its flight numbers, including this one, and those ran 76.4% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 351 | 365 | 83.6% | 42 min | 0.27% | B+ |
| All Delta Air Lines on SEA–HNL | 789 | 76.4% | 53 min | 0.38% | B+ |
| All carriers on SEA–HNL | 2,927 | 66.2% | 70 min | 1.13% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 351 quarter by quarter
DL 351 did not run the same all year. Its best quarter was Apr–Jun 2026 at 92.2% on time and its weakest Jan–Mar 2026 at 77.0%, a swing of 15 points on roughly 73 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights90.0%
- Oct–Dec 202592 flights81.3%
- Jan–Mar 202690 flights77.0%
- Apr–Jun 202691 flights92.2%
- Jul–Sep 202662 flights80.3%
Scale runs 70% to 100%.
By weekday, DL 351 did best on Wednesday at 92.3% on time and worst on Tuesday at 71.2%. Each day rests on about 52 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 351 runs when it is late
DL 351 often beats the schedule: 126 of 359 completed flights, 35%, arrived 15 minutes or more early. Most of the lateness is short. 31 of the 59 late arrivals were under half an hour behind, and 10 reached an hour or more.
- 15+ min early126 flights35.1%
- Within 15 min174 flights48.5%
- 15–29 min late31 flights8.6%
- 30–59 min late18 flights5.0%
- 1–2 hours late8 flights2.2%
- 2+ hours late2 flights0.6%
Scale runs 0% to 100%.
Share of 359 completed flights by arrival against schedule.
A late pushback is often recovered here: of 24 departures that left 15 minutes late or more, 12 still arrived on time. In the other direction, 47 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at HNL.
The worst days
Worst days for DL 351
The latest arrival of the period was on 16 April 2026, 4 hours 30 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in December 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 16 April 2026 | 4 hours 30 minutes | Carrier |
| 19 December 2025 | 3 hours 22 minutes | Late-arriving aircraft |
| 11 December 2025 | 1 hour 56 minutes | Carrier |
| 15 March 2026 | 1 hour 20 minutes | National Airspace System |
| 16 December 2025 | 1 hour 19 minutes | National Airspace System |
Delay causes
Why DL 351 runs late
National Airspace System accounts for 64% of the 2,455 delay minutes carriers reported here, and the remaining four split what is left.
- 64%National Airspace System
- 29%Carrier
- 6%Late-arriving aircraft
- 1%Extreme weather
64% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 1,575 minutes out of 2,455, against a national NAS share of 21%. The split is drawn from 2,455 delay minutes reported on DL 351.
Cancellations are rare at 0.27%, 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.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 2.8% 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.
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.
Every one of the 365 flights under DL 351 in the data flew SEA to HNL. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 365 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking DL 351
For a booking, read DL 351 as 83.6% on time with 0.27% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- SEA to HNL, every carrier and departure
- HNL to SEA, the return direction
- Delta Air Lines 419 on the same route70.7%
- Alaska Airlines 626 on the same route62.4%
- Seattle-Tacoma International (SEA) delay statistics
- Daniel K. Inouye International (HNL) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.