Flight number record

DL 473

Delta Air Lines · Seattle to Boston

Route: SEA → BOS
Departs: 22:25
Flights: 363
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 473, check with Delta Air Lines.

DL 473 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 45 minutes on average. That rests on 363 flights, with a median arrival 9 minutes early.

Set against the rest of the country, DL 473's record is 6 points better than the US average of 77.3%. That gap is worth roughly 62 fewer late arrivals for every thousand flights.

On time

83.5%

Arrivals under 15 minutes late, of 357 completed flights

Avg delay

47 min

Across delayed arrivals only, not all flights

Cancelled

1.38%

National rate is 1.89%

1 hour+ late

3.4%

National rate is 8.3%

These figures cover 363 flights between September 2025 and August 2026. The median arrival is 9 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 473 flies

DL 473 flies SEA to BOS without a single fixed slot. Its most common scheduled departure was 22:25, used on 91 of 363 flights, with 22:05 (90 flights) and 23:15 (57 flights) next.

Departs 22:2591 flights25.1%
Departs 22:0590 flights24.8%
Departs 23:1557 flights15.7%

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 22:25 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 473 runs 13 points better at 83.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

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Against the route

DL 473 next to SEA to BOS

Every carrier on SEA to BOS combined arrived on time 75.1% of the time across 2,554 flights, so DL 473 is 8 points ahead of it. Delta flew 1,067 flights on the same city pair under all its flight numbers, including this one, and those ran 79.8% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 2 points.

DL 473 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 473thin sample	363	83.5%	47 min	1.38%	B
All Delta Air Lines on SEA–BOS	1,067	79.8%	71 min	1.69%	B
All carriers on SEA–BOS	2,554	75.1%	64 min	1.49%	B
Delta Air Lines, whole network	1,039,517	81.1%	71 min	1.74%	B

Across the year

DL 473 quarter by quarter

DL 473 did not run the same all year. Its best quarter was Jul–Sep 2026 at 90.2% on time and its weakest Jul–Sep 2025 at 70.0%, a swing of 20 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 flights70.0%
Oct–Dec 202590 flights85.6%
Jan–Mar 202690 flights79.3%
Apr–Jun 202691 flights85.4%
Jul–Sep 202662 flights90.2%

Scale runs 60% to 95%.

By weekday, DL 473 did best on Thursday at 90.2% on time and worst on Sunday at 77.6%. Each day rests on about 52 flights, so a gap of 13 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late DL 473 runs when it is late

DL 473 often beats the schedule: 131 of 357 completed flights, 37%, arrived 15 minutes or more early. Most of the lateness is short. 30 of the 59 late arrivals were under half an hour behind, and 12 reached an hour or more.

15+ min early131 flights36.7%
Within 15 min167 flights46.8%
15–29 min late30 flights8.4%
30–59 min late17 flights4.8%
1–2 hours late10 flights2.8%
2+ hours late2 flights0.6%

Scale runs 0% to 100%.

Share of 357 completed flights by arrival against schedule.

A late pushback is often recovered here: of 74 departures that left 15 minutes late or more, 34 still arrived on time. In the other direction, 19 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 BOS.

The worst days

Worst days for DL 473

The latest arrival of the period was on 23 February 2026, 7 hours 16 minutes behind schedule; most of its delay minutes were filed as extreme weather. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).

The latest arrivals of DL 473 in the period
Date	Arrived late by	Largest filed cause
23 February 2026	7 hours 16 minutes	Extreme weather
19 September 2025	2 hours 19 minutes	Carrier
5 August 2026	1 hour 50 minutes	Carrier
25 February 2026	1 hour 49 minutes	Carrier
9 September 2025	1 hour 35 minutes	Carrier

Delay causes

Why DL 473 runs late

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 2,788 reported delay minutes.

Carrier
37%
Late-arriving aircraft
24%
National Airspace System
20%
Extreme weather
19%

Extreme weather accounts for 19% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 3.2 times the usual weather exposure. The split is drawn from 2,788 delay minutes reported on DL 473.

Cancellations sit at 1.38% against a national 1.89%, which is ordinary. Diversions add another 0.28%.

Connections and routes

What a delay on this flight costs

Badly late arrivals are rare here: only 3.4% 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 2,496 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 363 flights under DL 473 in the data flew SEA to BOS. 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. 363 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 473

For a booking, read DL 473 as 83.5% on time with 1.38% cancelled over 363 flights. Those are rates from the past twelve months, not a forecast for any particular 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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures