Flight number record

DL 1601

Delta Air Lines · Atlanta to Houston

Route: ATL → IAH
Departs: 22:40
Flights: 365
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 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 C−. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land about 50 minutes behind schedule. That rests on 365 flights, with a median arrival 4 minutes early.

On time

74.8%

Arrivals under 15 minutes late, of 353 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

3.29%

National rate is 1.81%

1 hour+ late

7.6%

National rate is 8.1%

These figures cover 365 flights between July 2025 and June 2026. The median arrival is 4 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 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 (66 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 22:40125 flights34.2%
Departs 22:4466 flights18.1%

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 22:40 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and DL 1601 runs 4 points better at 74.8%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

DL 1601 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 1601 is 2 points behind 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%, which this flight trails by 7 points.

DL 1601 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1601	365	74.8%	49 min	3.29%	C−
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 1601 quarter by quarter

Quarter by quarter DL 1601 held fairly steady: 75.3% in Jul–Sep 2025, 69.7% in Oct–Dec 2025, 77.9% in Jan–Mar 2026 and 76.4% in Apr–Jun 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Jul–Sep 202592 flights75.3%
Oct–Dec 202592 flights69.7%
Jan–Mar 202690 flights77.9%
Apr–Jun 202691 flights76.4%

Scale runs 60% to 85%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1601 did best on Saturday at 85.1% on time and worst on Friday at 66.7%. Each day rests on about 52 flights, so a gap of 18 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1601 runs late

One category carries most of the weight here. Carrier accounts for 48% of the 4,383 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.

Carrier
48%
Late-arriving aircraft
28%
National Airspace System
16%
Extreme weather
8%

The largest share of delay minutes, 48%, 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 2,098 of the 4,383 delay minutes reported here. The split is drawn from 4,383 delay minutes reported on DL 1601.

Cancellations run at 3.29%, 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

7.6% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 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. 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.

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, the cancellation rate is the figure to plan around on DL 1601: 3.29% of its 365 scheduled flights did not operate. A late arrival costs about 50 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures