Flight number record
DL 1601
Delta Air Lines · Atlanta to Houston
- Route
- ATL → IAH
- Departs
- 22:40
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1601, check with Delta Air Lines.
DL 1601 sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.3%. The late ones land roughly 50 minutes behind schedule. That rests on 365 flights, with a median arrival 5 minutes early.
Key figures
On time
75.0%
Arrivals under 15 minutes late, of 356 completed flights
Avg delay
52 min
Across delayed arrivals only, not all flights
Cancelled
2.47%
National rate is 1.89%
1 hour+ late
8.1%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. Beyond the headline rate, 8.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1601 flies
DL 1601 flies ATL to IAH without a single fixed slot. Its most common scheduled departure was 22:40, used on 125 of 365 flights, with 22:44 (72 flights) and 22:48 (60 flights) next.
- Departs 22:40125 flights34.2%
- Departs 22:4472 flights19.7%
- Departs 22:4860 flights16.4%
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 22:40 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 1601 runs 5 points better at 75.0%. 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 1601 next to ATL to IAH
Every carrier on ATL to IAH combined arrived on time 76.9% of the time across 4,965 flights, so DL 1601 is 2 points behind it. Delta flew 2,543 flights on the same city pair under all its flight numbers, including this one, and those ran 76.0% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 6 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1601 | 365 | 75.0% | 52 min | 2.47% | B |
| All Delta Air Lines on ATL–IAH | 2,543 | 76.0% | 57 min | 1.97% | B |
| All carriers on ATL–IAH | 4,965 | 76.9% | 69 min | 1.79% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1601 quarter by quarter
DL 1601 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Jul–Sep 2026 at 67.7%, a swing of 26 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 flights93.3%
- Oct–Dec 202592 flights69.7%
- Jan–Mar 202690 flights77.9%
- Apr–Jun 202691 flights76.4%
- Jul–Sep 202662 flights67.7%
Scale runs 60% to 100%.
By weekday, DL 1601 did best on Tuesday at 86.5% on time and worst on Friday at 62.7%. Each day rests on about 52 flights, so a gap of 24 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1601 runs when it is late
DL 1601 often beats the schedule: 91 of 356 completed flights, 26%, arrived 15 minutes or more early. The 89 late arrivals split 35 under half an hour, 25 between 30 and 60 minutes, and 29 an hour or more.
- 15+ min early91 flights25.6%
- Within 15 min176 flights49.4%
- 15–29 min late35 flights9.8%
- 30–59 min late25 flights7.0%
- 1–2 hours late23 flights6.5%
- 2+ hours late6 flights1.7%
Scale runs 0% to 100%.
Share of 356 completed flights by arrival against schedule.
26 of 101 late departures made up the time and arrived on time, 26% of them. 14 flights left on time and still arrived late.
The worst days
Worst days for DL 1601
The latest arrival of the period was on 8 December 2025, 3 hours 20 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in December 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 8 December 2025 | 3 hours 20 minutes | Late-arriving aircraft |
| 11 August 2026 | 2 hours 39 minutes | Carrier |
| 11 December 2025 | 2 hours 37 minutes | Late-arriving aircraft |
| 17 July 2026 | 2 hours 37 minutes | Late-arriving aircraft |
| 7 December 2025 | 2 hours 29 minutes | Late-arriving aircraft |
Delay causes
Why DL 1601 runs late
Carrier accounts for 48% of the 4,597 delay minutes carriers reported here, and the remaining four split what is left.
- 48%Carrier
- 35%Late-arriving aircraft
- 14%National Airspace System
- 3%Extreme weather
35% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,597 reported delay minutes here, that single category outweighs weather by 10 to one. The split is drawn from 4,597 delay minutes reported on DL 1601.
Cancellations sit at 2.47% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
8.1% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 50 minutes, which a normal layover absorbs.
The 689 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.
Every one of the 365 flights under DL 1601 in the data flew ATL to IAH. 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. 365 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 1601
For a booking, read DL 1601 as 75.0% on time with 2.47% cancelled over 365 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to IAH, every carrier and departure
- IAH to ATL, the return direction
- Delta Air Lines 1284 on the same route71.6%
- Delta Air Lines 1682 on the same route84.5%
- Frontier Airlines 4075 on the same route61.3%
- Delta Air Lines 1585 on the same route82.3%
- Frontier Airlines 1403 on the same route74.7%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- George Bush Intercontinental (IAH) 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.