Flight number record
DL 2511
Delta Air Lines · Atlanta to Rochester
- Route
- ATL → ROC
- Departs
- 09:48
- Flights
- 361
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 2511, check with Delta Air Lines.
DL 2511 lands a B, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That is a workable record, not a spotless one. That rests on 361 flights, with a median arrival 4 minutes early.
Set against the rest of the country, DL 2511's record is 5 points better than the US average of 77.6%. That gap is worth roughly 49 fewer late arrivals for every thousand flights.
Key figures
On time
82.5%
Arrivals under 15 minutes late, of 354 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
1.66%
National rate is 1.81%
1 hour+ late
3.1%
National rate is 8.1%
These figures cover 361 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 2511 flies
DL 2511 flies ATL to ROC without a single fixed slot. Its most common scheduled departure was 09:48, used on 55 of 361 flights. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 09:4855 flights15.2%
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 09:48 departure sits in the 8am–11am window. Across every US flight scheduled in that window the on-time rate is 84.1%, and DL 2511 runs level with that at 82.5%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
Against the route
DL 2511 next to ATL to ROC
Every carrier on ATL to ROC combined arrived on time 77.7% of the time across 1,040 flights, so DL 2511 is 5 points ahead of it. Across its whole network Delta Air Lines managed 81.6%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2511thin sample | 361 | 82.5% | 45 min | 1.66% | B |
| All Delta Air Lines on ATL–ROC | 1,040 | 77.7% | 55 min | 2.50% | B |
| All carriers on ATL–ROC | 1,040 | 77.7% | 55 min | 2.50% | B |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | B |
Across the year
DL 2511 quarter by quarter
DL 2511 did not run the same all year. Its best quarter was Apr–Jun 2026 at 92.0% on time and its weakest Oct–Dec 2025 at 75.0%, a swing of 17 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 202592 flights83.7%
- Oct–Dec 202592 flights75.0%
- Jan–Mar 202688 flights79.1%
- Apr–Jun 202689 flights92.0%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
By weekday, DL 2511 did best on Thursday at 90.2% on time and worst on Friday at 76.9%. Each day rests on about 52 flights, so a gap of 13 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 2511 runs late
One category carries most of the weight here. Carrier accounts for 47% of the 2,781 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.
- 47%Carrier
- 38%Late-arriving aircraft
- 15%National Airspace System
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 2,781 reported delay minutes here, that single category outweighs weather by 38 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 2,781 delay minutes reported on DL 2511.
Cancellations sit at 1.66% against a national 1.81%, which is ordinary. Diversions add another 0.28%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 3.1% land an hour or more behind schedule, against 8.1% 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 749 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.
DL 2511 is not only a ATL to ROC flight. It also flew ROC to ATL (361 flights, 80.1% 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.
| Also flown as | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| ROC to ATLthin sample | 361 | 80.1% | 59 min | 1.94% | B |
What to do with this
Booking DL 2511
For a booking, read DL 2511 as 82.5% on time with 1.66% cancelled over 361 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to ROC, every carrier and departure
- ROC to ATL, the return direction
- Delta Air Lines 2472 on the same route74.9%
- Delta Air Lines 2047 on the same route75.6%
- Hartsfield-Jackson Atlanta International (ATL) 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
- Why the first flight of the morning is statistically safest
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.