Flight number record

DL 1579

Delta Air Lines · Atlanta to Miami

Route: ATL → MIA
Departs: 12:15
Flights: 361
Period: September 2025 to August 2026

Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1579, check with Delta Air Lines.

DL 1579 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 361 flights, with a median arrival 1 minute early.

On time

75.3%

Arrivals under 15 minutes late, of 356 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

0.83%

National rate is 1.89%

1 hour+ late

7.0%

National rate is 8.3%

These figures cover 361 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.

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Schedule

When DL 1579 flies

DL 1579 flies ATL to MIA without a single fixed slot. Its most common scheduled departure was 12:15, used on 60 of 361 flights, with 12:20 (58 flights) and 13:55 (40 flights) next.

Departs 12:1560 flights16.6%
Departs 12:2058 flights16.1%
Departs 13:5540 flights11.1%

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 12:15 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.3%, and DL 1579 runs 3 points worse at 75.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

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Against the route

DL 1579 next to ATL to MIA

Every carrier on ATL to MIA combined arrived on time 71.2% of the time across 6,280 flights, so DL 1579 is 4 points ahead of it. Delta flew 3,321 flights on the same city pair under all its flight numbers, including this one, and those ran 71.4% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 6 points.

DL 1579 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1579thin sample	361	75.3%	49 min	0.83%	B+
All Delta Air Lines on ATL–MIA	3,321	71.4%	56 min	1.81%	C
All carriers on ATL–MIA	6,280	71.2%	73 min	1.61%	C
Delta Air Lines, whole network	1,039,517	81.1%	71 min	1.74%	B

Across the year

DL 1579 quarter by quarter

DL 1579 did not run the same all year. Its best quarter was Apr–Jun 2026 at 89.0% on time and its weakest Oct–Dec 2025 at 67.8%, a swing of 21 points on roughly 90 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 flights—
Oct–Dec 202592 flights67.8%
Jan–Mar 202686 flights68.2%
Apr–Jun 202691 flights89.0%
Jul–Sep 202662 flights73.8%

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1579 did best on Thursday at 78.8% on time and worst on Sunday at 63.5%. Each day rests on about 52 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Arrival by arrival

How late DL 1579 runs when it is late

The 88 late arrivals split 31 under half an hour, 32 between 30 and 60 minutes, and 25 an hour or more.

15+ min early44 flights12.4%
Within 15 min224 flights62.9%
15–29 min late31 flights8.7%
30–59 min late32 flights9.0%
1–2 hours late21 flights5.9%
2+ hours late4 flights1.1%

Scale runs 0% to 100%.

Share of 356 completed flights by arrival against schedule.

19 of 81 late departures made up the time and arrived on time, 23% of them. In the other direction, 26 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 MIA.

The worst days

Worst days for DL 1579

The latest arrival of the period was on 22 December 2025, 2 hours 45 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in December 2025.

The latest arrivals of DL 1579 in the period
Date	Arrived late by	Largest filed cause
22 December 2025	2 hours 45 minutes	Carrier
20 December 2025	2 hours 28 minutes	Carrier
4 August 2026	2 hours 5 minutes	National Airspace System
7 December 2025	2 hours 2 minutes	Late-arriving aircraft
2 August 2026	1 hour 53 minutes	National Airspace System

Delay causes

Why DL 1579 runs late

Carrier accounts for 51% of the 4,274 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
51%
National Airspace System
36%
Late-arriving aircraft
11%
Extreme weather
2%

36% 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 1,527 minutes out of 4,274, against a national NAS share of 21%. The split is drawn from 4,274 delay minutes reported on DL 1579.

Cancellations are rare at 0.83%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and routes

What a delay on this flight costs

7.0% 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 594 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 1579 is not only a ATL to MIA flight. It also flew MIA to ATL (325 flights, 67.1% 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. 361 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 1579
Also flown as	Flights	On time	Avg delay	Cancelled	Grade
MIA to ATLthin sample	325	67.1%	84 min	0.62%	C+

What to do with this

Booking DL 1579

For a booking, read DL 1579 as 75.3% on time with 0.83% cancelled over 361 flights. Those are rates from the past twelve months, not a forecast for any particular day.

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