Flight number record

DL 503

Delta Air Lines · Atlanta to Portland

Route: ATL → PDX
Departs: 16:51
Flights: 351
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 503, check with Delta Air Lines.

DL 503 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 351 flights, with a median arrival right on schedule.

The national on-time rate over the same period is 77.3%, so DL 503 runs 5 points behind the country as a whole. Across a thousand flights that is about 45 extra late arrivals.

On time

72.8%

Arrivals under 15 minutes late, of 349 completed flights

Avg delay

57 min

Across delayed arrivals only, not all flights

Cancelled

0.57%

National rate is 1.89%

1 hour+ late

6.9%

National rate is 8.3%

These figures cover 351 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

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Schedule

When DL 503 flies

DL 503 flies ATL to PDX without a single fixed slot. Its most common scheduled departure was 16:51, used on 52 of 351 flights, with 17:15 (39 flights) and 16:48 (37 flights) next.

Departs 16:5152 flights14.8%
Departs 17:1539 flights11.1%
Departs 16:4837 flights10.5%

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 16:51 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 503 runs level with that at 72.8%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

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Against the route

DL 503 next to ATL to PDX

Every carrier on ATL to PDX combined arrived on time 78.4% of the time across 1,545 flights, so DL 503 is 6 points behind it. Delta flew 1,257 flights on the same city pair under all its flight numbers, including this one, and those ran 77.5% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 8 points.

DL 503 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 503thin sample	351	72.8%	57 min	0.57%	C+
All Delta Air Lines on ATL–PDX	1,257	77.5%	48 min	0.95%	B+
All carriers on ATL–PDX	1,545	78.4%	50 min	0.91%	B+
Delta Air Lines, whole network	1,039,517	81.1%	71 min	1.74%	B

Across the year

DL 503 quarter by quarter

DL 503 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jul–Sep 2026 at 63.9%, a swing of 29 points on roughly 70 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 flights93.3%
Oct–Dec 202590 flights66.7%
Jan–Mar 202679 flights72.7%
Apr–Jun 202691 flights78.0%
Jul–Sep 202661 flights63.9%

Scale runs 55% to 100%.

By weekday, DL 503 did best on Saturday at 82.6% on time and worst on Sunday at 58.3%. Each day rests on about 50 flights, so a gap of 24 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late DL 503 runs when it is late

The 95 late arrivals split 40 under half an hour, 31 between 30 and 60 minutes, and 24 an hour or more.

15+ min early56 flights16.0%
Within 15 min198 flights56.7%
15–29 min late40 flights11.5%
30–59 min late31 flights8.9%
1–2 hours late16 flights4.6%
2+ hours late8 flights2.3%

Scale runs 0% to 100%.

Share of 349 completed flights by arrival against schedule.

Time lost at the gate mostly stays lost. Of 63 departures that left 15 minutes late or more, only 5 made it up before arrival. In the other direction, 37 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 PDX.

The worst days

Worst days for DL 503

The latest arrival of the period was on 20 October 2025, 6 hours 13 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 July 2026.

The latest arrivals of DL 503 in the period
Date	Arrived late by	Largest filed cause
20 October 2025	6 hours 13 minutes	Carrier
12 July 2026	4 hours 46 minutes	Carrier
24 July 2026	4 hours 32 minutes	Late-arriving aircraft
8 November 2025	4 hours 14 minutes	Extreme weather
3 July 2026	3 hours 17 minutes	Late-arriving aircraft

Delay causes

Why DL 503 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 5,404 reported delay minutes.

Carrier
41%
National Airspace System
33%
Late-arriving aircraft
20%
Extreme weather
7%

The largest share of delay minutes, 41%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,200 of the 5,404 delay minutes reported here. The split is drawn from 5,404 delay minutes reported on DL 503.

Cancellations are rare at 0.57%, 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

6.9% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.

At 2,172 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 351 flights under DL 503 in the data flew ATL to PDX. 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. 351 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 503

For a booking, DL 503 is one of the weaker ways to fly ATL to PDX: 6 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.

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