Flight number record

DL 473

Delta Air Lines · Seattle to Boston

Route: SEA → BOS
Departs: 22:05
Flights: 363
Period: July 2025 to June 2026

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

DL 473 lands a B, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That is a workable record, not a spotless one. That rests on 363 flights, with a median arrival 7 minutes early.

On time

80.3%

Arrivals under 15 minutes late, of 356 completed flights

Avg delay

41 min

Across delayed arrivals only, not all flights

Cancelled

1.65%

National rate is 1.81%

1 hour+ late

3.1%

National rate is 8.1%

These figures cover 363 flights between July 2025 and June 2026. The median arrival is 7 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 473 flies

DL 473 flies SEA to BOS without a single fixed slot. Its most common scheduled departure was 22:05, used on 111 of 363 flights, with 22:25 (91 flights) and 23:00 (47 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 22:05111 flights30.6%
Departs 22:2591 flights25.1%
Departs 23:0047 flights12.9%

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 22:05 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and DL 473 runs 10 points better at 80.3%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

DL 473 next to SEA to BOS

Every carrier on SEA to BOS combined arrived on time 74.5% of the time across 2,459 flights, so DL 473 is 6 points ahead of it. Delta flew 1,005 flights on the same city pair under all its flight numbers, including this one, and those ran 81.2% on time. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.

DL 473 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 473thin sample	363	80.3%	41 min	1.65%	B
All Delta Air Lines on SEA–BOS	1,005	81.2%	68 min	1.49%	B
All carriers on SEA–BOS	2,459	74.5%	68 min	1.14%	C
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 473 quarter by quarter

DL 473 did not run the same all year. Its best quarter was Oct–Dec 2025 at 85.6% on time and its weakest Jul–Sep 2025 at 71.1%, 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 flights71.1%
Oct–Dec 202590 flights85.6%
Jan–Mar 202690 flights79.3%
Apr–Jun 202691 flights85.4%

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, DL 473 did best on Wednesday at 86.5% on time and worst on Saturday at 71.2%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

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 2,891 reported delay minutes.

Carrier
38%
National Airspace System
24%
Late-arriving aircraft
20%
Extreme weather
18%

Extreme weather accounts for 18% 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 2.9 times the usual weather exposure. The split is drawn from 2,891 delay minutes reported on DL 473.

Cancellations sit at 1.65% against a national 1.81%, 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 3.1% 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 2,496 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 80.3% on time with 1.65% 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures