Flight number record
DL 1403
Delta Air Lines · Atlanta to St. Louis
- Route
- ATL → STL
- Departs
- 23:15
- Flights
- 330
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1403, check with Delta Air Lines.
DL 1403 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 50 minutes on average. That rests on 330 flights, with a median arrival 6 minutes early.
Set against the rest of the country, DL 1403's record is 6 points better than the US average of 77.3%. That gap is worth roughly 57 fewer late arrivals for every thousand flights.
Key figures
On time
83.0%
Arrivals under 15 minutes late, of 324 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
1.82%
National rate is 1.89%
1 hour+ late
4.6%
National rate is 8.3%
These figures cover 330 flights between September 2025 and August 2026. The median arrival is 6 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 1403 flies
DL 1403 flies ATL to STL without a single fixed slot. Its most common scheduled departure was 23:15, used on 53 of 330 flights, with 23:10 (49 flights) and 23:00 (47 flights) next.
- Departs 23:1553 flights16.1%
- Departs 23:1049 flights14.8%
- Departs 23:0047 flights14.2%
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 23:15 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 1403 runs 13 points better at 83.0%. 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 1403 next to ATL to STL
Every carrier on ATL to STL combined arrived on time 81.8% of the time across 3,678 flights, so DL 1403 is about level with it. Delta flew 2,348 flights on the same city pair under all its flight numbers, including this one, and those ran 84.6% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1403thin sample | 330 | 83.0% | 49 min | 1.82% | B |
| All Delta Air Lines on ATL–STL | 2,348 | 84.6% | 56 min | 1.87% | B |
| All carriers on ATL–STL | 3,678 | 81.8% | 56 min | 1.41% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1403 quarter by quarter
DL 1403 did not run the same all year. Its best quarter was Jul–Sep 2025 at 100.0% on time and its weakest Oct–Dec 2025 at 75.0%, a swing of 25 points on roughly 66 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 flights100.0%
- Oct–Dec 202557 flights75.0%
- Jan–Mar 202690 flights80.5%
- Apr–Jun 202691 flights84.4%
- Jul–Sep 202662 flights83.6%
Scale runs 65% to 100%.
By weekday, DL 1403 did best on Saturday at 90.5% on time and worst on Monday at 74.5%. Each day rests on about 47 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1403 runs when it is late
The 55 late arrivals split 18 under half an hour, 22 between 30 and 60 minutes, and 15 an hour or more.
- 15+ min early66 flights20.4%
- Within 15 min203 flights62.7%
- 15–29 min late18 flights5.6%
- 30–59 min late22 flights6.8%
- 1–2 hours late13 flights4.0%
- 2+ hours late2 flights0.6%
Scale runs 0% to 100%.
Share of 324 completed flights by arrival against schedule.
8 of 50 late departures made up the time and arrived on time, 16% of them. 13 flights left on time and still arrived late.
The worst days
Worst days for DL 1403
The latest arrival of the period was on 14 December 2025, 2 hours 38 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 |
|---|---|---|
| 14 December 2025 | 2 hours 38 minutes | Carrier |
| 13 March 2026 | 2 hours 34 minutes | Carrier |
| 17 November 2025 | 1 hour 56 minutes | Carrier |
| 6 July 2026 | 1 hour 47 minutes | Carrier |
| 11 August 2026 | 1 hour 38 minutes | Carrier |
Delay causes
Why DL 1403 runs late
Carrier accounts for 54% of the 2,682 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Carrier
- 25%Late-arriving aircraft
- 17%National Airspace System
- 5%Extreme weather
The largest share of delay minutes, 54%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 1,442 of the 2,682 delay minutes reported here. The split is drawn from 2,682 delay minutes reported on DL 1403.
Cancellations sit at 1.82% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 4.6% 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.
Every one of the 330 flights under DL 1403 in the data flew ATL to STL. 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. 330 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 1403
For a booking, read DL 1403 as 83.0% on time with 1.82% cancelled over 330 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to STL, every carrier and departure
- STL to ATL, the return direction
- Delta Air Lines 1571 on the same route91.8%
- Delta Air Lines 1393 on the same route78.7%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- St. Louis Lambert International (STL) 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.