Flight number record
DL 903
Delta Air Lines · Atlanta to Seattle
- Route
- ATL → SEA
- Departs
- 21:35
- Flights
- 288
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 903, check with Delta Air Lines.
DL 903 lands a B, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 288 flights, with a median arrival 4 minutes early.
Key figures
On time
77.7%
Arrivals under 15 minutes late, of 282 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
1.74%
National rate is 1.89%
1 hour+ late
5.3%
National rate is 8.3%
These figures cover 288 flights between September 2025 and August 2026. The median arrival is 4 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 903 flies
DL 903 flies ATL to SEA without a single fixed slot. Its most common scheduled departure was 21:35, used on 86 of 288 flights, with 21:20 (77 flights) and 21:25 (55 flights) next.
- Departs 21:3586 flights29.9%
- Departs 21:2077 flights26.7%
- Departs 21:2555 flights19.1%
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 21:35 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 903 runs 8 points better at 77.7%. 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 903 next to ATL to SEA
Every carrier on ATL to SEA combined arrived on time 76.7% of the time across 3,297 flights, so DL 903 is about level with it. Delta flew 2,404 flights on the same city pair under all its flight numbers, including this one, and those ran 76.8% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 3 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 903thin sample | 288 | 77.7% | 60 min | 1.74% | B |
| All Delta Air Lines on ATL–SEA | 2,404 | 76.8% | 58 min | 0.62% | B+ |
| All carriers on ATL–SEA | 3,297 | 76.7% | 57 min | 0.73% | B+ |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 903 quarter by quarter
DL 903 did not run the same all year. Its best quarter was Jul–Sep 2025 at 96.7% on time and its weakest Jul–Sep 2026 at 72.4%, a swing of 24 points on roughly 72 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 flights96.7%
- Oct–Dec 202592 flights80.0%
- Jan–Mar 202618 flights—
- Apr–Jun 202686 flights73.3%
- Jul–Sep 202662 flights72.4%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 903 did best on Tuesday at 86.5% on time and worst on Sunday at 69.8%. Each day rests on about 41 flights, so a gap of 17 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 903 runs when it is late
DL 903 often beats the schedule: 77 of 282 completed flights, 27%, arrived 15 minutes or more early. The 63 late arrivals split 30 under half an hour, 18 between 30 and 60 minutes, and 15 an hour or more.
- 15+ min early77 flights27.3%
- Within 15 min142 flights50.4%
- 15–29 min late30 flights10.6%
- 30–59 min late18 flights6.4%
- 1–2 hours late11 flights3.9%
- 2+ hours late4 flights1.4%
Scale runs 0% to 100%.
Share of 282 completed flights by arrival against schedule.
17 of 68 late departures made up the time and arrived on time, 25% of them. 12 flights left on time and still arrived late.
The worst days
Worst days for DL 903
The latest arrival of the period was on 17 May 2026, 10 hours 10 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 17 May 2026 | 10 hours 10 minutes | Carrier |
| 13 August 2026 | 8 hours 3 minutes | Carrier |
| 3 July 2026 | 2 hours 59 minutes | Carrier |
| 7 August 2026 | 2 hours 19 minutes | Carrier |
| 18 June 2026 | 1 hour 58 minutes | Carrier |
Delay causes
Why DL 903 runs late
Carrier accounts for 77% of the 3,808 delay minutes carriers reported here, and the remaining four split what is left.
- 77%Carrier
- 13%Late-arriving aircraft
- 9%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 77%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,939 of the 3,808 delay minutes reported here. The split is drawn from 3,808 delay minutes reported on DL 903.
Cancellations sit at 1.74% against a national 1.89%, which is ordinary. Diversions add another 0.35%.
Connections and routes
What a delay on this flight costs
5.3% 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 2,182 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.
The same number turns up on one other city pair in the data, including ATL to BWI (42), but none flew often enough under DL 903 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to SEA only.
One caution: this is a thin sample. 288 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 903
For a booking, read DL 903 as 77.7% on time with 1.74% cancelled over 288 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to SEA, every carrier and departure
- SEA to ATL, the return direction
- Delta Air Lines 629 on the same route80.4%
- Delta Air Lines 774 on the same route84.6%
- Delta Air Lines 444 on the same route78.3%
- Delta Air Lines 481 on the same route78.4%
- Delta Air Lines 714 on the same route65.0%
- Alaska Airlines 377 on the same route85.3%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
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 ; recomputed monthly. How this data is collected.