Flight number record
DL 1233
Delta Air Lines · New York to Austin
- Route
- JFK → AUS
- Departs
- 17:40
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1233, check with Delta Air Lines.
DL 1233 lands a B−, level with the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 364 flights, with a median arrival 11 minutes early.
Key figures
On time
76.8%
Arrivals under 15 minutes late, of 349 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
3.85%
National rate is 1.89%
1 hour+ late
10.0%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 10.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1233 flies
DL 1233 flies JFK to AUS without a single fixed slot. Its most common scheduled departure was 17:40, used on 90 of 364 flights, with 18:10 (43 flights) and 18:15 (40 flights) next.
- Departs 17:4090 flights24.7%
- Departs 18:1043 flights11.8%
- Departs 18:1540 flights11.0%
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 17:40 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 1233 runs 9 points better at 76.8%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 1233 next to JFK to AUS
Every carrier on JFK to AUS combined arrived on time 80.8% of the time across 2,227 flights, so DL 1233 is 4 points behind it. Delta flew 1,283 flights on the same city pair under all its flight numbers, including this one, and those ran 83.2% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1233thin sample | 364 | 76.8% | 73 min | 3.85% | B− |
| All Delta Air Lines on JFK–AUS | 1,283 | 83.2% | 66 min | 3.20% | B− |
| All carriers on JFK–AUS | 2,227 | 80.8% | 96 min | 3.46% | B− |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1233 quarter by quarter
DL 1233 did not run the same all year. Its best quarter was Apr–Jun 2026 at 82.2% on time and its weakest Oct–Dec 2025 at 70.5%, a swing of 12 points on roughly 73 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 202530 flights76.7%
- Oct–Dec 202591 flights70.5%
- Jan–Mar 202690 flights81.2%
- Apr–Jun 202691 flights82.2%
- Jul–Sep 202662 flights71.4%
Scale runs 60% to 90%.
By weekday, DL 1233 did best on Friday at 86.0% on time and worst on Sunday at 68.8%. Each day rests on about 52 flights, so a gap of 17 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1233 runs when it is late
DL 1233 often beats the schedule: 162 of 349 completed flights, 46%, arrived 15 minutes or more early. The 81 late arrivals split 23 under half an hour, 23 between 30 and 60 minutes, and 35 an hour or more.
- 15+ min early162 flights46.4%
- Within 15 min106 flights30.4%
- 15–29 min late23 flights6.6%
- 30–59 min late23 flights6.6%
- 1–2 hours late24 flights6.9%
- 2+ hours late11 flights3.2%
Scale runs 0% to 100%.
Share of 349 completed flights by arrival against schedule.
19 of 77 late departures made up the time and arrived on time, 25% of them. In the other direction, 23 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 AUS.
The worst days
Worst days for DL 1233
The latest arrival of the period was on 30 October 2025, 6 hours 34 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 30 October 2025 | 6 hours 34 minutes | Late-arriving aircraft |
| 20 May 2026 | 5 hours 36 minutes | Extreme weather |
| 24 February 2026 | 4 hours 26 minutes | Late-arriving aircraft |
| 31 October 2025 | 3 hours 45 minutes | Late-arriving aircraft |
| 3 July 2026 | 2 hours 59 minutes | Late-arriving aircraft |
Delay causes
Why DL 1233 runs late
Late-arriving aircraft accounts for 45% of the 5,909 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Late-arriving aircraft
- 28%National Airspace System
- 21%Carrier
- 6%Extreme weather
45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,909 reported delay minutes here, that single category outweighs weather by 8 to one. The split is drawn from 5,909 delay minutes reported on DL 1233.
Cancellations run at 3.85%, against 1.89% nationally. That is about one flight in 25 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
10.0% 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.
At 1,521 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
Every one of the 364 flights under DL 1233 in the data flew JFK to AUS. 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. 364 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 1233
For a booking, the cancellation rate is the figure to plan around on DL 1233: 3.85% of its 364 scheduled flights did not operate. A late arrival costs a little over an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- JFK to AUS, every carrier and departure
- AUS to JFK, the return direction
- Delta Air Lines 2323 on the same route81.7%
- American Airlines 2772 on the same route75.6%
- John F. Kennedy International (JFK) delay statistics
- Austin-Bergstrom International (AUS) 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
- Why the first flight of the morning is statistically safest
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.