Flight number record
DL 520
Delta Air Lines · Atlanta to New York
- Route
- ATL → LGA
- Departs
- 21:30
- Flights
- 364
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 520, check with Delta Air Lines.
DL 520 sits in the middle of the pack with a C−. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 364 flights, with a median arrival 1 minute early.
The national on-time rate over the same period is 77.3%, so DL 520 runs 8 points behind the country as a whole. Across a thousand flights that is about 78 extra late arrivals.
Key figures
On time
69.5%
Arrivals under 15 minutes late, of 347 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
4.12%
National rate is 1.89%
1 hour+ late
10.4%
National rate is 8.3%
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 10.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 520 flies
DL 520 flies ATL to LGA without a single fixed slot. Its most common scheduled departure was 21:30, used on 215 of 364 flights, with 21:00 (127 flights) next.
- Departs 21:30215 flights59.1%
- Departs 21:00127 flights34.9%
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 21:30 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 520 runs level with that at 69.5%. 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 520 next to ATL to LGA
Every carrier on ATL to LGA combined arrived on time 72.3% of the time across 8,502 flights, so DL 520 is 3 points behind it. Delta flew 4,937 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 81.1%, which this flight trails by 12 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 520thin sample | 364 | 69.5% | 57 min | 4.12% | C− |
| All Delta Air Lines on ATL–LGA | 4,937 | 75.9% | 66 min | 3.48% | B− |
| All carriers on ATL–LGA | 8,502 | 72.3% | 79 min | 4.34% | C− |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 520 quarter by quarter
DL 520 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 57.9%, a swing of 35 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 202591 flights67.4%
- Jan–Mar 202690 flights73.3%
- Apr–Jun 202691 flights67.0%
- Jul–Sep 202662 flights57.9%
Scale runs 50% to 100%.
By weekday, DL 520 did best on Wednesday at 84.0% on time and worst on Monday at 57.7%. Each day rests on about 52 flights, so a gap of 26 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 520 runs when it is late
The 106 late arrivals split 36 under half an hour, 34 between 30 and 60 minutes, and 36 an hour or more.
- 15+ min early62 flights17.9%
- Within 15 min179 flights51.6%
- 15–29 min late36 flights10.4%
- 30–59 min late34 flights9.8%
- 1–2 hours late29 flights8.4%
- 2+ hours late7 flights2.0%
Scale runs 0% to 100%.
Share of 347 completed flights by arrival against schedule.
21 of 114 late departures made up the time and arrived on time, 18% of them. 13 flights left on time and still arrived late.
The worst days
Worst days for DL 520
The latest arrival of the period was on 4 July 2026, 3 hours 50 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. Three of the five worst days fell in December 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 4 July 2026 | 3 hours 50 minutes | National Airspace System |
| 6 August 2026 | 3 hours 48 minutes | Late-arriving aircraft |
| 7 December 2025 | 3 hours 44 minutes | Extreme weather |
| 19 December 2025 | 3 hours 12 minutes | National Airspace System |
| 14 December 2025 | 2 hours 39 minutes | National Airspace System |
Delay causes
Why DL 520 runs late
National Airspace System accounts for 45% of the 6,055 delay minutes carriers reported here, and the remaining four split what is left.
- 45%National Airspace System
- 27%Late-arriving aircraft
- 23%Carrier
- 5%Extreme weather
45% 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 2,751 minutes out of 6,055, against a national NAS share of 21%. The split is drawn from 6,055 delay minutes reported on DL 520.
Cancellations run at 4.12%, against 1.89% nationally. That is about one flight in 25 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
10.4% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 762 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 364 flights under DL 520 in the data flew ATL to LGA. 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. 364 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 520
For a booking, the cancellation rate is the figure to plan around on DL 520: 4.12% of its 364 scheduled flights did not operate. A late arrival costs about an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ATL to LGA, every carrier and departure
- LGA to ATL, the return direction
- Frontier Airlines 3288 on the same route36.9%
- Delta Air Lines 513 on the same route87.7%
- Delta Air Lines 997 on the same route67.1%
- Delta Air Lines 371 on the same route84.7%
- Delta Air Lines 434 on the same route62.1%
- Delta Air Lines 460 on the same route76.3%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- LaGuardia (LGA) 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
- How often a connection fails at the major US hubs
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.