Flight number record
DL 1323
Delta Air Lines · Atlanta to Miami
- Route
- ATL → MIA
- Departs
- 13:45
- Flights
- 363
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1323, check with Delta Air Lines.
DL 1323 draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 50 minutes behind schedule. Build slack into anything you connect to. That rests on 363 flights, with a median arrival 5 minutes late.
The national on-time rate over the same period is 77.3%, so DL 1323 runs 15 points behind the country as a whole. Across a thousand flights that is about 149 extra late arrivals.
Key figures
On time
62.4%
Arrivals under 15 minutes late, of 356 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
1.38%
National rate is 1.89%
1 hour+ late
11.2%
National rate is 8.3%
These figures cover 363 flights between September 2025 and August 2026. Beyond the headline rate, 11.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1323 flies
DL 1323 flies ATL to MIA without a single fixed slot. Its most common scheduled departure was 13:45, used on 81 of 363 flights, with 16:25 (52 flights) next.
- Departs 13:4581 flights22.3%
- Departs 16:2552 flights14.3%
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 13:45 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 1323 runs 16 points worse at 62.4%. 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 1323 next to ATL to MIA
Every carrier on ATL to MIA combined arrived on time 71.2% of the time across 6,280 flights, so DL 1323 is 9 points behind it. Delta flew 3,321 flights on the same city pair under all its flight numbers, including this one, and those ran 71.4% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 19 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1323thin sample | 363 | 62.4% | 52 min | 1.38% | D |
| All Delta Air Lines on ATL–MIA | 3,321 | 71.4% | 56 min | 1.81% | C |
| All carriers on ATL–MIA | 6,280 | 71.2% | 73 min | 1.61% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1323 quarter by quarter
Quarter by quarter DL 1323 held fairly steady: 58.9% in Oct–Dec 2025, 64.0% in Jan–Mar 2026, 67.0% in Apr–Jun 2026 and 62.3% in Jul–Sep 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202529 flights—
- Oct–Dec 202591 flights58.9%
- Jan–Mar 202690 flights64.0%
- Apr–Jun 202691 flights67.0%
- Jul–Sep 202662 flights62.3%
Scale runs 50% to 70%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1323 did best on Wednesday at 75.0% on time and worst on Sunday at 50.0%. Each day rests on about 52 flights, so a gap of 25 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1323 runs when it is late
The 134 late arrivals split 47 under half an hour, 47 between 30 and 60 minutes, and 40 an hour or more.
- 15+ min early40 flights11.2%
- Within 15 min182 flights51.1%
- 15–29 min late47 flights13.2%
- 30–59 min late47 flights13.2%
- 1–2 hours late31 flights8.7%
- 2+ hours late9 flights2.5%
Scale runs 0% to 100%.
Share of 356 completed flights by arrival against schedule.
21 of 113 late departures made up the time and arrived on time, 19% of them. In the other direction, 42 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 MIA.
The worst days
Worst days for DL 1323
The latest arrival of the period was on 11 October 2025, 4 hours 21 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across October, September, August, May and April, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 October 2025 | 4 hours 21 minutes | Carrier |
| 8 September 2025 | 3 hours 25 minutes | National Airspace System |
| 11 August 2026 | 2 hours 50 minutes | National Airspace System |
| 21 May 2026 | 2 hours 25 minutes | Late-arriving aircraft |
| 28 April 2026 | 2 hours 18 minutes | Carrier |
Delay causes
Why DL 1323 runs late
National Airspace System accounts for 43% of the 6,923 delay minutes carriers reported here, and the remaining four split what is left.
- 43%National Airspace System
- 39%Carrier
- 14%Late-arriving aircraft
- 4%Extreme weather
43% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,947 minutes out of 6,923, against a national NAS share of 21%. The split is drawn from 6,923 delay minutes reported on DL 1323.
Cancellations sit at 1.38% against a national 1.89%, which is ordinary. Diversions add another 0.55%.
Connections and routes
What a delay on this flight costs
11.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 594 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
DL 1323 is not only a ATL to MIA flight. It also flew MIA to ATL (290 flights, 59.9% on time) often enough to be scored on its own. Airlines attach one number to several legs of an aircraft's day, and each leg keeps its own record here, so check which city pair is on your booking before reading a rate.
One caution: this is a thin sample. 363 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| MIA to ATLthin sample | 290 | 59.9% | 77 min | 2.07% | D |
What to do with this
Booking DL 1323
For a booking, DL 1323 is one of the weaker ways to fly ATL to MIA: 9 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.
Related
Where to go next
- ATL to MIA, every carrier and departure
- MIA to ATL, the return direction
- Delta Air Lines 1510 on the same route83.7%
- Delta Air Lines 1332 on the same route82.2%
- Delta Air Lines 1588 on the same route64.2%
- Delta Air Lines 1579 on the same route75.3%
- Frontier Airlines 4406 on the same route72.5%
- Delta Air Lines 2836 on the same route89.8%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Miami International (MIA) 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
- How often a connection fails at the major US hubs
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.