Flight number record

DL 629

Delta Air Lines · Atlanta to Seattle

Route: ATL → SEA
Departs: 11:30
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 629, check with Delta Air Lines.

DL 629 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 45 minutes on average. That is a workable record, not a spotless one. That rests on 365 flights, with a median arrival 5 minutes early.

On time

80.7%

Arrivals under 15 minutes late, of 363 completed flights

Avg delay

47 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

National rate is 1.81%

1 hour+ late

3.3%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 5 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 629 flies

DL 629 flies ATL to SEA without a single fixed slot. Its most common scheduled departure was 11:30, used on 50 of 365 flights, with 12:00 (47 flights) and 11:45 (38 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 11:3050 flights13.7%
Departs 12:0047 flights12.9%
Departs 11:4538 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 11:30 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and DL 629 runs level with that at 80.7%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

DL 629 next to ATL to SEA

Every carrier on ATL to SEA combined arrived on time 77.8% of the time across 3,277 flights, so DL 629 is 3 points ahead of it. Delta flew 2,371 flights on the same city pair under all its flight numbers, including this one, and those ran 79.1% on time. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.

DL 629 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 629	365	80.7%	47 min	0.27%	B+
All Delta Air Lines on ATL–SEA	2,371	79.1%	53 min	0.46%	B+
All carriers on ATL–SEA	3,277	77.8%	54 min	0.64%	B+
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 629 quarter by quarter

DL 629 did not run the same all year. Its best quarter was Jul–Sep 2025 at 89.1% on time and its weakest Jan–Mar 2026 at 72.7%, a swing of 16 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 flights89.1%
Oct–Dec 202592 flights76.1%
Jan–Mar 202690 flights72.7%
Apr–Jun 202691 flights84.6%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, DL 629 did best on Sunday at 90.4% on time and worst on Saturday at 76.5%. Each day rests on about 52 flights, so a gap of 14 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 629 runs late

One category carries most of the weight here. Carrier accounts for 63% of the 3,299 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.

Carrier
63%
National Airspace System
23%
Late-arriving aircraft
14%
Extreme weather
1%

The largest share of delay minutes, 63%, 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 2,065 of the 3,299 delay minutes reported here. The split is drawn from 3,299 delay minutes reported on DL 629.

Cancellations are rare at 0.27%, 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 3.3% 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 2,182 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 629 in the data flew ATL to SEA. 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 629

For a booking, read DL 629 as 80.7% on time with 0.27% cancelled over 365 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