Flight number record
DL 1585
Delta Air Lines · Atlanta to Houston
- Route
- ATL → IAH
- Departs
- 07:35
- Flights
- 325
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1585, check with Delta Air Lines.
DL 1585 lands a B−, 4 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 40 minutes on average. That is a workable record, not a spotless one. That rests on 325 flights, with a median arrival 2 minutes early.
Key figures
On time
81.2%
Arrivals under 15 minutes late, of 313 completed flights
Avg delay
40 min
Across delayed arrivals only, not all flights
Cancelled
3.38%
National rate is 1.81%
1 hour+ late
2.6%
National rate is 8.1%
These figures cover 325 flights between July 2025 and June 2026. The median arrival is 2 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.
Schedule
When DL 1585 flies
DL 1585 flies ATL to IAH without a single fixed slot. Its most common scheduled departure was 07:35, used on 96 of 325 flights, with 07:30 (82 flights) and 07:25 (55 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 07:3596 flights29.5%
- Departs 07:3082 flights25.2%
- Departs 07:2555 flights16.9%
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 07:35 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and DL 1585 runs 8 points worse at 81.2%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
DL 1585 next to ATL to IAH
Every carrier on ATL to IAH combined arrived on time 76.4% of the time across 4,914 flights, so DL 1585 is 5 points ahead of it. Delta flew 2,508 flights on the same city pair under all its flight numbers, including this one, and those ran 75.9% on time. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1585thin sample | 325 | 81.2% | 40 min | 3.38% | B− |
| All Delta Air Lines on ATL–IAH | 2,508 | 75.9% | 55 min | 1.95% | B |
| All carriers on ATL–IAH | 4,914 | 76.4% | 67 min | 1.87% | B |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 1585 quarter by quarter
DL 1585 did not run the same all year. Its best quarter was Jan–Mar 2026 at 93.9% on time and its weakest Oct–Dec 2025 at 72.2%, a swing of 22 points on roughly 81 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 202571 flights81.7%
- Oct–Dec 202577 flights72.2%
- Jan–Mar 202686 flights93.9%
- Apr–Jun 202691 flights76.1%
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, DL 1585 ranged from 77.1% on Monday to 85.4% on Wednesday. With about 46 flights behind each day, a spread of 8 points is inside normal variation, so the day you fly is not worth changing for this flight.
Delay causes
Why DL 1585 runs late
One category carries most of the weight here. National Airspace System accounts for 53% of the 2,352 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.
- 53%National Airspace System
- 36%Carrier
- 9%Extreme weather
- 2%Late-arriving aircraft
The largest share of delay minutes, 36%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 855 of the 2,352 delay minutes reported here. The split is drawn from 2,352 delay minutes reported on DL 1585.
Cancellations run at 3.38%, against 1.81% nationally. That is about one flight in 30 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
Badly late arrivals are rare here: only 2.6% land an hour or more behind schedule, against 8.1% 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 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. 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 1585 is not only a ATL to IAH flight. It also flew IAH to ATL (322 flights, 77.8% 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. 325 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 |
|---|---|---|---|---|---|
| IAH to ATLthin sample | 322 | 77.8% | 58 min | 3.42% | B− |
What to do with this
Booking DL 1585
For a booking, the cancellation rate is the figure to plan around on DL 1585: 3.38% of its 325 scheduled flights did not operate. A late arrival costs about 40 minutes, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ATL to IAH, every carrier and departure
- IAH to ATL, the return direction
- Delta Air Lines 1601 on the same route74.8%
- Delta Air Lines 1284 on the same route73.6%
- Delta Air Lines 1682 on the same route82.1%
- Frontier Airlines 4075 on the same route63.4%
- Frontier Airlines 1403 on the same route72.3%
- 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
- 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.