Flight number record

DL 351

Delta Air Lines · Seattle to Honolulu

Route: SEA → HNL
Departs: 08:45
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 351, check with Delta Air Lines.

DL 351 earns an 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 roughly 50 minutes. That rests on 365 flights, with a median arrival 8 minutes early.

Set against the rest of the country, DL 351's record is 8 points better than the US average of 77.6%. That gap is worth roughly 76 fewer late arrivals for every thousand flights.

On time

85.2%

Arrivals under 15 minutes late, of 359 completed flights

Avg delay

52 min

Across delayed arrivals only, not all flights

Cancelled

0.55%

National rate is 1.81%

1 hour+ late

3.6%

National rate is 8.1%

These figures cover 365 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.

Schedule

When DL 351 flies

DL 351 flies SEA to HNL without a single fixed slot. Its most common scheduled departure was 08:45, used on 131 of 365 flights, with 08:35 (41 flights) and 07:15 (38 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 08:45131 flights35.9%
Departs 08:3541 flights11.2%
Departs 07:1538 flights10.4%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 08:45 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 351 runs level with that at 85.2%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.

Against the route

DL 351 next to SEA to HNL

Every carrier on SEA to HNL combined arrived on time 65.5% of the time across 2,938 flights, so DL 351 is 20 points ahead of it. Delta flew 789 flights on the same city pair under all its flight numbers, including this one, and those ran 77.9% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight beats by 4 points.

DL 351 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 351	365	85.2%	52 min	0.55%	A+
All Delta Air Lines on SEA–HNL	789	77.9%	56 min	0.76%	B+
All carriers on SEA–HNL	2,938	65.5%	71 min	0.99%	C+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	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 91 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 202592 flights90.1%
Oct–Dec 202592 flights81.3%
Jan–Mar 202690 flights77.0%
Apr–Jun 202691 flights92.2%

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 351 did best on Wednesday at 92.2% on time and worst on Tuesday at 79.2%. Each day rests on about 52 flights, so a gap of 13 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 351 runs late

One category carries most of the weight here. National Airspace System accounts for 51% of the 2,755 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.

National Airspace System
51%
Carrier
44%
Late-arriving aircraft
4%
Extreme weather
1%

The largest share of delay minutes, 44%, 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 1,210 of the 2,755 delay minutes reported here. The split is drawn from 2,755 delay minutes reported on DL 351.

Cancellations are rare at 0.55%, below the national 1.81% 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 3.6% 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.

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, DL 351 has one of the better records a US domestic flight can show: 85.2% on time and 0.55% cancelled. That is a base rate, not a promise about any single day.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures