Flight number record

DL 1403

Delta Air Lines · Atlanta to St. Louis

Route: ATL → STL
Departs: 23:00
Flights: 330
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1403, check with Delta Air Lines.

DL 1403 lands a B, 2 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 55 minutes on average. That is a workable record, not a spotless one. That rests on 330 flights, with a median arrival 5 minutes early.

On time

79.3%

Arrivals under 15 minutes late, of 324 completed flights

Avg delay

53 min

Across delayed arrivals only, not all flights

Cancelled

1.52%

National rate is 1.81%

1 hour+ late

6.5%

National rate is 8.1%

These figures cover 330 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 1403 flies

DL 1403 flies ATL to STL without a single fixed slot. Its most common scheduled departure was 23:00, used on 46 of 330 flights, with 23:15 (36 flights) and 23:11 (35 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 23:0046 flights13.9%
Departs 23:1536 flights10.9%
Departs 23:1135 flights10.6%

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 23:00 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and DL 1403 runs 9 points better at 79.3%. 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 1403 next to ATL to STL

Every carrier on ATL to STL combined arrived on time 82.4% of the time across 3,706 flights, so DL 1403 is 3 points behind it. Delta flew 2,371 flights on the same city pair under all its flight numbers, including this one, and those ran 84.7% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 2 points.

DL 1403 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1403thin sample	330	79.3%	53 min	1.52%	B
All Delta Air Lines on ATL–STL	2,371	84.7%	55 min	1.98%	B
All carriers on ATL–STL	3,706	82.4%	56 min	1.54%	B
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	B

Across the year

DL 1403 quarter by quarter

Quarter by quarter DL 1403 held fairly steady: 75.8% in Jul–Sep 2025, 75.0% in Oct–Dec 2025, 80.5% in Jan–Mar 2026 and 84.4% in Apr–Jun 2026. A spread of 9 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights75.8%
Oct–Dec 202557 flights75.0%
Jan–Mar 202690 flights80.5%
Apr–Jun 202691 flights84.4%

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

By weekday, DL 1403 did best on Tuesday at 86.0% on time and worst on Friday at 67.3%. Each day rests on about 47 flights, so a gap of 19 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1403 runs late

One category carries most of the weight here. Carrier accounts for 44% of the 3,543 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
44%
Late-arriving aircraft
37%
National Airspace System
14%
Extreme weather
6%

37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 3,543 reported delay minutes here, that single category outweighs weather by 6 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 3,543 delay minutes reported on DL 1403.

Cancellations sit at 1.52% against a national 1.81%, which is ordinary. Diversions add another 0.30%.

Connections and routes

What a delay on this flight costs

6.5% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 55 minutes, which a normal layover absorbs.

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 79.3% on time with 1.52% cancelled over 330 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