Flight number record
DL 1323
Delta Air Lines · Atlanta to Miami
- Route
- ATL → MIA
- Departs
- 13:45
- Flights
- 360
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 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 55 minutes behind schedule. Build slack into anything you connect to. That rests on 360 flights, with a median arrival 7 minutes late.
The national on-time rate over the same period is 77.6%, so DL 1323 runs 17 points behind the country as a whole. Across a thousand flights that is about 173 extra late arrivals.
Key figures
On time
60.3%
Arrivals under 15 minutes late, of 353 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
1.39%
National rate is 1.81%
1 hour+ late
11.9%
National rate is 8.1%
These figures cover 360 flights between July 2025 and June 2026. Beyond the headline rate, 11.9% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
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 360 flights, with 16:13 (40 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 13:4581 flights22.5%
- Departs 16:1340 flights11.1%
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 13:45 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and DL 1323 runs 19 points worse at 60.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
DL 1323 next to ATL to MIA
Every carrier on ATL to MIA combined arrived on time 71.0% of the time across 6,229 flights, so DL 1323 is 11 points behind it. Delta flew 3,298 flights on the same city pair under all its flight numbers, including this one, and those ran 70.3% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 21 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1323thin sample | 360 | 60.3% | 54 min | 1.39% | D |
| All Delta Air Lines on ATL–MIA | 3,298 | 70.3% | 56 min | 1.43% | C |
| All carriers on ATL–MIA | 6,229 | 71.0% | 71 min | 1.41% | C |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 1323 quarter by quarter
DL 1323 did not run the same all year. Its best quarter was Apr–Jun 2026 at 67.0% on time and its weakest Jul–Sep 2025 at 51.2%, a swing of 16 points on roughly 90 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 202588 flights51.2%
- Oct–Dec 202591 flights58.9%
- Jan–Mar 202690 flights64.0%
- Apr–Jun 202691 flights67.0%
Scale runs 45% to 70%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1323 did best on Wednesday at 73.1% on time and worst on Sunday at 46.0%. Each day rests on about 51 flights, so a gap of 27 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 1323 runs late
One category carries most of the weight here. Carrier accounts for 42% of the 7,520 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.
- 42%Carrier
- 40%National Airspace System
- 15%Late-arriving aircraft
- 2%Extreme weather
40% 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 3,038 minutes out of 7,520, against a national NAS share of 21%. The split is drawn from 7,520 delay minutes reported on DL 1323.
Cancellations sit at 1.39% against a national 1.81%, which is ordinary. Diversions add another 0.56%.
Connections and routes
What a delay on this flight costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.9% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
DL 1323 is not only a ATL to MIA flight. It also flew MIA to ATL (289 flights, 57.6% 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. 360 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 | 289 | 57.6% | 91 min | 2.08% | 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: 11 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 route82.5%
- Delta Air Lines 1332 on the same route79.2%
- Delta Air Lines 1588 on the same route65.5%
- Delta Air Lines 1579 on the same route73.6%
- Delta Air Lines 2836 on the same route88.6%
- Frontier Airlines 4406 on the same route72.8%
- 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
- The best time of day to fly, according to 7.04 million flight records
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.