Flight number record
DL 519
Delta Air Lines · Atlanta to Denver
- Route
- ATL → DEN
- Departs
- 16:35
- Flights
- 365
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 519, check with Delta Air Lines.
DL 519 draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is roughly 55 minutes behind schedule. Build slack into anything you connect to. That rests on 365 flights, with a median arrival 2 minutes late.
The national on-time rate over the same period is 77.3%, so DL 519 runs 11 points behind the country as a whole. Across a thousand flights that is about 106 extra late arrivals.
Key figures
On time
66.7%
Arrivals under 15 minutes late, of 360 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
0.82%
National rate is 1.89%
1 hour+ late
11.1%
National rate is 8.3%
These figures cover 365 flights between September 2025 and August 2026. Beyond the headline rate, 11.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Schedule
When DL 519 flies
DL 519 flies ATL to DEN without a single fixed slot. Its most common scheduled departure was 16:35, used on 61 of 365 flights, with 16:30 (45 flights) and 18:04 (38 flights) next.
- Departs 16:3561 flights16.7%
- Departs 16:3045 flights12.3%
- Departs 18:0438 flights10.4%
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 16:35 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 519 runs 5 points worse at 66.7%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Against the route
DL 519 next to ATL to DEN
Every carrier on ATL to DEN combined arrived on time 78.0% of the time across 5,594 flights, so DL 519 is 11 points behind it. Delta flew 2,807 flights on the same city pair under all its flight numbers, including this one, and those ran 79.0% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 14 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 519 | 365 | 66.7% | 53 min | 0.82% | C+ |
| All Delta Air Lines on ATL–DEN | 2,807 | 79.0% | 52 min | 1.21% | B |
| All carriers on ATL–DEN | 5,594 | 78.0% | 61 min | 1.11% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 519 quarter by quarter
DL 519 did not run the same all year. Its best quarter was Jan–Mar 2026 at 77.0% on time and its weakest Jul–Sep 2026 at 50.8%, a swing of 26 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 flights76.7%
- Oct–Dec 202592 flights63.7%
- Jan–Mar 202690 flights77.0%
- Apr–Jun 202691 flights67.0%
- Jul–Sep 202662 flights50.8%
Scale runs 40% to 80%.
By weekday, DL 519 did best on Wednesday at 76.9% on time and worst on Sunday at 57.7%. Each day rests on about 52 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 519 runs when it is late
The 120 late arrivals split 35 under half an hour, 45 between 30 and 60 minutes, and 40 an hour or more.
- 15+ min early53 flights14.7%
- Within 15 min187 flights51.9%
- 15–29 min late35 flights9.7%
- 30–59 min late45 flights12.5%
- 1–2 hours late33 flights9.2%
- 2+ hours late7 flights1.9%
Scale runs 0% to 100%.
Share of 360 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 89 departures that left 15 minutes late or more, only 9 made it up before arrival. In the other direction, 40 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 DEN.
The worst days
Worst days for DL 519
The latest arrival of the period was on 11 August 2026, 3 hours 13 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across August, December, March and July, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 August 2026 | 3 hours 13 minutes | National Airspace System |
| 7 December 2025 | 2 hours 59 minutes | Carrier |
| 6 March 2026 | 2 hours 39 minutes | Extreme weather |
| 15 August 2026 | 2 hours 22 minutes | Carrier |
| 9 July 2026 | 2 hours 13 minutes | Extreme weather |
Delay causes
Why DL 519 runs late
National Airspace System accounts for 44% of the 6,345 delay minutes carriers reported here, and the remaining four split what is left.
- 44%National Airspace System
- 33%Carrier
- 17%Late-arriving aircraft
- 6%Extreme weather
44% 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 2,800 minutes out of 6,345, against a national NAS share of 21%. The split is drawn from 6,345 delay minutes reported on DL 519.
Cancellations are rare at 0.82%, 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
11.1% 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 1,199 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.
The same number turns up on one other city pair in the data, including DEN to ATL (12), but none flew often enough under DL 519 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to DEN only.
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 519
For a booking, DL 519 is one of the weaker ways to fly ATL to DEN: 11 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- ATL to DEN, every carrier and departure
- DEN to ATL, the return direction
- United Airlines 235 on the same route78.5%
- Delta Air Lines 746 on the same route67.8%
- Delta Air Lines 706 on the same route84.7%
- Frontier Airlines 3293 on the same route81.2%
- Delta Air Lines 530 on the same route80.5%
- United Airlines 340 on the same route91.1%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Denver International (DEN) 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 7.05 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.