Flight number record

DL 1585

Delta Air Lines · Atlanta to Houston

Route: ATL → IAH
Departs: 07:30
Flights: 334
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1585, check with Delta Air Lines.

DL 1585 lands a B−, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 40 minutes on average. That rests on 334 flights, with a median arrival 3 minutes early.

Set against the rest of the country, DL 1585's record is 5 points better than the US average of 77.3%. That gap is worth roughly 50 fewer late arrivals for every thousand flights.

On time

82.3%

Arrivals under 15 minutes late, of 317 completed flights

Avg delay

39 min

Across delayed arrivals only, not all flights

Cancelled

4.79%

National rate is 1.89%

1 hour+ late

2.2%

National rate is 8.3%

These figures cover 334 flights between September 2025 and August 2026. The median arrival is 3 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 1585 flies

DL 1585 flies ATL to IAH without a single fixed slot. Its most common scheduled departure was 07:30, used on 110 of 334 flights, with 07:35 (61 flights) and 07:25 (54 flights) next.

Departs 07:30110 flights32.9%
Departs 07:3561 flights18.3%
Departs 07:2554 flights16.2%

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 07:30 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 7 points worse at 82.3%. 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 1585 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 1585 is 5 points ahead of 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%, close to this flight's figure.

DL 1585 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1585thin sample	334	82.3%	39 min	4.79%	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 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 84 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 202519 flights—
Oct–Dec 202577 flights72.2%
Jan–Mar 202686 flights93.9%
Apr–Jun 202691 flights76.1%
Jul–Sep 202661 flights89.3%

Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1585 ranged from 78.7% on Tuesday to 87.1% on Saturday. With about 48 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.

Arrival by arrival

How late DL 1585 runs when it is late

Most of the lateness is short. 36 of the 56 late arrivals were under half an hour behind, and 7 reached an hour or more.

15+ min early63 flights19.9%
Within 15 min198 flights62.5%
15–29 min late36 flights11.4%
30–59 min late13 flights4.1%
1–2 hours late3 flights0.9%
2+ hours late4 flights1.3%

Scale runs 0% to 100%.

Share of 317 completed flights by arrival against schedule.

8 of 30 late departures made up the time and arrived on time, 27% of them. In the other direction, 34 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 IAH.

The worst days

Worst days for DL 1585

The latest arrival of the period was on 7 December 2025, 3 hours 56 minutes behind schedule; most of its delay minutes were filed as extreme weather. The five worst days are spread across December, November, June, January and March, with no single month standing out.

The latest arrivals of DL 1585 in the period
Date	Arrived late by	Largest filed cause
7 December 2025	3 hours 56 minutes	Extreme weather
10 November 2025	2 hours 24 minutes	Carrier
21 June 2026	2 hours 24 minutes	National Airspace System
20 January 2026	2 hours 5 minutes	Carrier
16 March 2026	1 hour 53 minutes	National Airspace System

Delay causes

Why DL 1585 runs late

National Airspace System accounts for 56% of the 2,208 delay minutes carriers reported here, and the remaining four split what is left.

National Airspace System
56%
Carrier
33%
Extreme weather
9%
Late-arriving aircraft
2%

56% 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 1,232 minutes out of 2,208, against a national NAS share of 21%. The split is drawn from 2,208 delay minutes reported on DL 1585.

Cancellations run at 4.79%, against 1.89% nationally. That is about 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

Badly late arrivals are rare here: only 2.2% 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 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.

DL 1585 is not only a ATL to IAH flight. It also flew IAH to ATL (331 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. 334 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.

Other routes flown as DL 1585
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
IAH to ATLthin sample	331	77.8%	63 min	4.83%	B−

What to do with this

Booking DL 1585

For a booking, the cancellation rate is the figure to plan around on DL 1585: 4.79% of its 334 scheduled flights did not operate. A late arrival costs about 40 minutes, but a cancellation costs the day, so leave a later option open.

Where to go next

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 22 October 2026; recomputed monthly. How this data is collected.

Key figures