Flight number record
DL 865
Delta Air Lines · Atlanta to Boston
- Route
- ATL → BOS
- Departs
- 22:40
- Flights
- 360
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 865, check with Delta Air Lines.
DL 865 lands a B−, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 360 flights, with a median arrival 9 minutes early.
Key figures
On time
80.2%
Arrivals under 15 minutes late, of 348 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
3.33%
National rate is 1.89%
1 hour+ late
6.6%
National rate is 8.3%
These figures cover 360 flights between September 2025 and August 2026. The median arrival is 9 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.
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Schedule
When DL 865 flies
DL 865 flies ATL to BOS without a single fixed slot. Its most common scheduled departure was 22:40, used on 117 of 360 flights, with 22:50 (60 flights) and 22:35 (55 flights) next.
- Departs 22:40117 flights32.5%
- Departs 22:5060 flights16.7%
- Departs 22:3555 flights15.3%
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 22:40 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 865 runs 10 points better at 80.2%. 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 865 next to ATL to BOS
Every carrier on ATL to BOS combined arrived on time 72.8% of the time across 5,054 flights, so DL 865 is 7 points ahead of it. Delta flew 3,731 flights on the same city pair under all its flight numbers, including this one, and those ran 74.4% on time. Across its whole network Delta Air Lines managed 81.1%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 865thin sample | 360 | 80.2% | 76 min | 3.33% | B− |
| All Delta Air Lines on ATL–BOS | 3,731 | 74.4% | 61 min | 1.82% | C |
| All carriers on ATL–BOS | 5,054 | 72.8% | 66 min | 2.30% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 865 quarter by quarter
DL 865 did not run the same all year. Its best quarter was Jul–Sep 2025 at 100.0% on time and its weakest Jul–Sep 2026 at 71.2%, a swing of 29 points on roughly 72 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 flights100.0%
- Oct–Dec 202587 flights77.4%
- Jan–Mar 202690 flights77.6%
- Apr–Jun 202691 flights84.4%
- Jul–Sep 202662 flights71.2%
Scale runs 65% to 100%.
By weekday, DL 865 did best on Wednesday at 88.5% on time and worst on Thursday at 70.0%. Each day rests on about 51 flights, so a gap of 19 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 865 runs when it is late
DL 865 often beats the schedule: 124 of 348 completed flights, 36%, arrived 15 minutes or more early. The 69 late arrivals split 26 under half an hour, 20 between 30 and 60 minutes, and 23 an hour or more.
- 15+ min early124 flights35.6%
- Within 15 min155 flights44.5%
- 15–29 min late26 flights7.5%
- 30–59 min late20 flights5.7%
- 1–2 hours late14 flights4.0%
- 2+ hours late9 flights2.6%
Scale runs 0% to 100%.
Share of 348 completed flights by arrival against schedule.
A late pushback is often recovered here: of 87 departures that left 15 minutes late or more, 27 still arrived on time. 9 flights left on time and still arrived late.
The worst days
Worst days for DL 865
The latest arrival of the period was on 23 February 2026, 13 hours 33 minutes behind schedule; most of its delay minutes were filed as extreme weather. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 23 February 2026 | 13 hours 33 minutes | Extreme weather |
| 11 November 2025 | 8 hours 26 minutes | Carrier |
| 24 February 2026 | 7 hours 34 minutes | Carrier |
| 5 December 2025 | 3 hours 12 minutes | Late-arriving aircraft |
| 14 June 2026 | 2 hours 48 minutes | Carrier |
Delay causes
Why DL 865 runs late
Carrier accounts for 51% of the 5,273 delay minutes carriers reported here, and the remaining four split what is left.
- 51%Carrier
- 24%Late-arriving aircraft
- 17%Extreme weather
- 7%National Airspace System
Extreme weather accounts for 17% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.9 times the usual weather exposure. The split is drawn from 5,273 delay minutes reported on DL 865.
Cancellations run at 3.33%, against 1.89% 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
6.6% 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 a little over an hour, which a normal layover absorbs.
The 946 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 360 flights under DL 865 in the data flew ATL to BOS. 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. 360 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 865
For a booking, the cancellation rate is the figure to plan around on DL 865: 3.33% of its 360 scheduled flights did not operate. A late arrival costs a little over an hour, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- ATL to BOS, every carrier and departure
- BOS to ATL, the return direction
- Delta Air Lines 855 on the same route85.2%
- Delta Air Lines 726 on the same route66.3%
- Delta Air Lines 821 on the same route69.2%
- Delta Air Lines 987 on the same route89.9%
- Delta Air Lines 350 on the same route74.6%
- Delta Air Lines 2595 on the same route62.5%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Boston Logan International (BOS) 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
- What a cancellation rate actually tells you (and what it hides)
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.