Flight number record
DL 1329
Delta Air Lines · Atlanta to Philadelphia
- Route
- ATL → PHL
- Departs
- 16:25
- Flights
- 309
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1329, check with Delta Air Lines.
DL 1329 draws a D−. Roughly one flight in two arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 309 flights, with a median arrival 8 minutes late.
The national on-time rate over the same period is 77.3%, so DL 1329 runs 18 points behind the country as a whole. Across a thousand flights that is about 183 extra late arrivals.
Key figures
On time
59.0%
Arrivals under 15 minutes late, of 295 completed flights
Avg delay
64 min
Across delayed arrivals only, not all flights
Cancelled
4.53%
National rate is 1.89%
1 hour+ late
12.5%
National rate is 8.3%
These figures cover 309 flights between September 2025 and August 2026. Beyond the headline rate, 12.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1329 flies
DL 1329 flies ATL to PHL without a single fixed slot. Its most common scheduled departure was 16:25, used on 44 of 309 flights, with 16:30 (43 flights) and 16:23 (36 flights) next.
- Departs 16:2544 flights14.2%
- Departs 16:3043 flights13.9%
- Departs 16:2336 flights11.7%
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 16:25 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 1329 runs 13 points worse at 59.0%. 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 1329 next to ATL to PHL
Every carrier on ATL to PHL combined arrived on time 74.6% of the time across 5,793 flights, so DL 1329 is 16 points behind it. Delta flew 3,020 flights on the same city pair under all its flight numbers, including this one, and those ran 76.2% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 22 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1329thin sample | 309 | 59.0% | 64 min | 4.53% | D− |
| All Delta Air Lines on ATL–PHL | 3,020 | 76.2% | 58 min | 3.11% | B− |
| All carriers on ATL–PHL | 5,793 | 74.6% | 81 min | 3.28% | C− |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1329 quarter by quarter
DL 1329 did not run the same all year. Its best quarter was Oct–Dec 2025 at 75.3% on time and its weakest Jul–Sep 2026 at 40.7%, a swing of 35 points on roughly 77 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 202520 flights—
- Oct–Dec 202580 flights75.3%
- Jan–Mar 202682 flights61.0%
- Apr–Jun 202665 flights48.4%
- Jul–Sep 202662 flights40.7%
Scale runs 30% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1329 did best on Saturday at 77.3% on time and worst on Thursday at 39.5%. Each day rests on about 44 flights, so a gap of 38 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1329 runs when it is late
The 121 late arrivals split 44 under half an hour, 40 between 30 and 60 minutes, and 37 an hour or more.
- 15+ min early16 flights5.4%
- Within 15 min158 flights53.6%
- 15–29 min late44 flights14.9%
- 30–59 min late40 flights13.6%
- 1–2 hours late21 flights7.1%
- 2+ hours late16 flights5.4%
Scale runs 0% to 100%.
Share of 295 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 91 departures that left 15 minutes late or more, only 9 made it up before arrival. In the other direction, 39 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 PHL.
The worst days
Worst days for DL 1329
The latest arrival of the period was on 28 July 2026, 5 hours 14 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in July 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 28 July 2026 | 5 hours 14 minutes | Carrier |
| 9 July 2026 | 4 hours 44 minutes | Late-arriving aircraft |
| 16 July 2026 | 4 hours 42 minutes | Carrier |
| 5 January 2026 | 4 hours 23 minutes | Carrier |
| 20 August 2026 | 4 hours 22 minutes | National Airspace System |
Delay causes
Why DL 1329 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 7,743 reported delay minutes.
- 40%Carrier
- 39%National Airspace System
- 19%Late-arriving aircraft
- 2%Extreme weather
39% 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 3,049 minutes out of 7,743, against a national NAS share of 21%. The split is drawn from 7,743 delay minutes reported on DL 1329.
Cancellations run at 4.53%, against 1.89% nationally. That is roughly one flight in twenty cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and routes
What a delay on this flight costs
12.5% 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 666 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 one other city pair in the data, including PHL to ATL (158), but none flew often enough under DL 1329 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to PHL only.
One caution: this is a thin sample. 309 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 1329
For a booking, the cancellation rate is the figure to plan around on DL 1329: 4.53% of its 309 scheduled flights did not operate. A late arrival costs about an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ATL to PHL, every carrier and departure
- PHL to ATL, the return direction
- Delta Air Lines 2642 on the same route76.6%
- Delta Air Lines 2270 on the same route87.3%
- Delta Air Lines 1169 on the same route70.0%
- Frontier Airlines 2298 on the same route68.2%
- Delta Air Lines 2065 on the same route63.5%
- Frontier Airlines 1102 on the same route45.7%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Philadelphia International (PHL) 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.