Flight number record
DL 1249
Delta Air Lines · Miami to Atlanta
- Route
- MIA → ATL
- Departs
- 06:00
- Flights
- 296
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1249, check with Delta Air Lines.
DL 1249 earns an A. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 15 points better than the national rate of 77.3%. When something does go wrong the average delay runs an hour and a half. That rests on 296 flights, with a median arrival 15 minutes early.
Set against the rest of the country, DL 1249's record is 15 points better than the US average of 77.3%. That gap is worth roughly 154 fewer late arrivals for every thousand flights.
Key figures
On time
92.7%
Arrivals under 15 minutes late, of 289 completed flights
Avg delay
92 min
Across delayed arrivals only, not all flights
Cancelled
2.36%
National rate is 1.89%
1 hour+ late
3.5%
National rate is 8.3%
These figures cover 296 flights between September 2025 and August 2026. The median arrival is 15 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 1249 flies
DL 1249 flies MIA to ATL without a single fixed slot. Its most common scheduled departure was 06:00, used on 217 of 296 flights, with 05:50 (38 flights) next.
- Departs 06:00217 flights73.3%
- Departs 05:5038 flights12.8%
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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1249 runs 3 points better at 92.7%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
DL 1249 next to MIA to ATL
Every carrier on MIA to ATL combined arrived on time 74.2% of the time across 6,271 flights, so DL 1249 is 19 points ahead of it. Delta flew 3,322 flights on the same city pair under all its flight numbers, including this one, and those ran 77.8% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight beats by 12 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1249thin sample | 296 | 92.7% | 92 min | 2.36% | A |
| All Delta Air Lines on MIA–ATL | 3,322 | 77.8% | 82 min | 1.78% | B |
| All carriers on MIA–ATL | 6,271 | 74.2% | 82 min | 1.59% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1249 quarter by quarter
DL 1249 did not run the same all year. Its best quarter was Apr–Jun 2026 at 98.9% on time and its weakest Oct–Dec 2025 at 74.5%, a swing of 24 points on roughly 74 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.
- Oct–Dec 202553 flights74.5%
- Jan–Mar 202690 flights95.5%
- Apr–Jun 202691 flights98.9%
- Jul–Sep 202662 flights94.9%
Scale runs 65% to 100%.
By weekday, DL 1249 ranged from 88.1% on Thursday to 97.6% on Saturday. With about 42 flights behind each day, a spread of 10 points is inside normal variation, so the day you fly is not worth changing for this flight.
Arrival by arrival
How late DL 1249 runs when it is late
DL 1249 often beats the schedule: 152 of 289 completed flights, 53%, arrived 15 minutes or more early. The 21 late arrivals split 7 under half an hour, 4 between 30 and 60 minutes, and 10 an hour or more.
- 15+ min early152 flights52.6%
- Within 15 min116 flights40.1%
- 15–29 min late7 flights2.4%
- 30–59 min late4 flights1.4%
- 1–2 hours late6 flights2.1%
- 2+ hours late4 flights1.4%
Scale runs 0% to 100%.
Share of 289 completed flights by arrival against schedule.
4 of 20 late departures made up the time and arrived on time, 20% of them. Only 5 left on time and still arrived late.
The worst days
Worst days for DL 1249
The latest arrival of the period was on 16 March 2026, 7 hours 25 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 16 March 2026 | 7 hours 25 minutes | National Airspace System |
| 13 December 2025 | 4 hours 54 minutes | Carrier |
| 31 July 2026 | 3 hours 33 minutes | Carrier |
| 5 July 2026 | 2 hours 40 minutes | Carrier |
| 27 November 2025 | 1 hour 49 minutes | Late-arriving aircraft |
Delay causes
Why DL 1249 runs late
Carrier accounts for 50% of the 1,934 delay minutes carriers reported here, and the remaining four split what is left.
- 50%Carrier
- 33%National Airspace System
- 17%Late-arriving aircraft
33% 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 636 minutes out of 1,934, against a national NAS share of 21%. The split is drawn from 1,934 delay minutes reported on DL 1249.
Cancellations sit at 2.36% 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 3.5% 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.
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.
The same number turns up on four other city pairs in the data, including ATL to MIA (41), GEG to SLC (1) and MCI to MSP (1), but none flew often enough under DL 1249 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to MIA to ATL only.
One caution: this is a thin sample. 296 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 1249
For a booking, read DL 1249 as 92.7% on time with 2.36% cancelled over 296 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- MIA to ATL, every carrier and departure
- ATL to MIA, the return direction
- Delta Air Lines 1510 on the same route83.5%
- Delta Air Lines 1332 on the same route73.7%
- Delta Air Lines 1261 on the same route93.1%
- Delta Air Lines 1211 on the same route92.5%
- Delta Air Lines 2836 on the same route87.0%
- Delta Air Lines 1386 on the same route58.1%
- Miami International (MIA) delay statistics
- Hartsfield-Jackson Atlanta International (ATL) 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 7.05 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.