Flight number record
DL 817
Delta Air Lines · Boston to Raleigh
- Route
- BOS → RDU
- Departs
- 20:05
- Flights
- 290
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 817, check with Delta Air Lines.
DL 817 earns an F−, which is as low as this site's scale goes for a reason. Only 54.1% of flights arrive inside the 15-minute window, 23 points worse than the national rate of 77.3%. Late arrivals average an hour and a half. Treat any tight connection here as a coin flip. That rests on 290 flights, with a median arrival 7 minutes late.
The national on-time rate over the same period is 77.3%, so DL 817 runs 23 points behind the country as a whole. Across a thousand flights that is about 232 extra late arrivals.
Key figures
On time
54.1%
Arrivals under 15 minutes late, of 281 completed flights
Avg delay
92 min
Across delayed arrivals only, not all flights
Cancelled
3.10%
National rate is 1.89%
1 hour+ late
26.7%
National rate is 8.3%
These figures cover 290 flights between September 2025 and August 2026. Beyond the headline rate, 26.7% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 817 flies
DL 817 flies BOS to RDU without a single fixed slot. Its most common scheduled departure was 20:05, used on 81 of 290 flights, with 19:49 (31 flights) and 19:45 (29 flights) next.
- Departs 20:0581 flights27.9%
- Departs 19:4931 flights10.7%
- Departs 19:4529 flights10.0%
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 20:05 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 817 runs 16 points worse at 54.1%. 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 817 next to BOS to RDU
Every carrier on BOS to RDU combined arrived on time 75.5% of the time across 2,848 flights, so DL 817 is 21 points behind it. Delta flew 1,436 flights on the same city pair under all its flight numbers, including this one, and those ran 77.1% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 27 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 817thin sample | 290 | 54.1% | 92 min | 3.10% | F− |
| All Delta Air Lines on BOS–RDU | 1,436 | 77.1% | 85 min | 2.65% | B |
| All carriers on BOS–RDU | 2,848 | 75.5% | 78 min | 2.95% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 817 quarter by quarter
DL 817 did not run the same all year. Its best quarter was Apr–Jun 2026 at 64.4% on time and its weakest Jul–Sep 2026 at 43.1%, a swing of 21 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 202526 flights—
- Oct–Dec 202563 flights48.4%
- Jan–Mar 202673 flights64.3%
- Apr–Jun 202675 flights64.4%
- Jul–Sep 202653 flights43.1%
Scale runs 35% to 70%. Rows with fewer than 30 flights show a dash.
By weekday, DL 817 did best on Wednesday at 66.7% on time and worst on Sunday at 38.6%. Each day rests on about 41 flights, so a gap of 28 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 817 runs when it is late
DL 817 often beats the schedule: 83 of 281 completed flights, 30%, arrived 15 minutes or more early. When DL 817 is late it tends to be very late: 75 of its 129 late arrivals were an hour or more behind, and 38 were two hours or more.
- 15+ min early83 flights29.5%
- Within 15 min69 flights24.6%
- 15–29 min late25 flights8.9%
- 30–59 min late29 flights10.3%
- 1–2 hours late37 flights13.2%
- 2+ hours late38 flights13.5%
Scale runs 0% to 100%.
Share of 281 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 132 departures that left 15 minutes late or more, only 15 made it up before arrival. 12 flights left on time and still arrived late.
The worst days
Worst days for DL 817
The latest arrival of the period was on 25 September 2025, 5 hours 2 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 25 September 2025 | 5 hours 2 minutes | Late-arriving aircraft |
| 15 June 2026 | 4 hours 51 minutes | Late-arriving aircraft |
| 19 October 2025 | 4 hours 28 minutes | Late-arriving aircraft |
| 5 June 2026 | 4 hours 13 minutes | Late-arriving aircraft |
| 7 August 2026 | 4 hours 4 minutes | Late-arriving aircraft |
Delay causes
Why DL 817 runs late
Late-arriving aircraft accounts for 72% of the 12,000 delay minutes carriers reported here, and the remaining four split what is left.
- 72%Late-arriving aircraft
- 20%Carrier
- 6%National Airspace System
- 2%Extreme weather
72% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 12,000 reported delay minutes here, that single category outweighs weather by 36 to one. The split is drawn from 11,859 delay minutes reported on DL 817.
Cancellations run at 3.10%, 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
26.7% 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 612 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 three other city pairs in the data, including ATL to MEM (11), AGS to ATL (3) and ATL to AGS (3), but none flew often enough under DL 817 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to RDU only.
One caution: this is a thin sample. 290 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 817
For a booking, the cancellation rate is the figure to plan around on DL 817: 3.10% of its 290 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.
Related
Where to go next
- BOS to RDU, every carrier and departure
- RDU to BOS, the return direction
- Delta Air Lines 2782 on the same route72.6%
- Delta Air Lines 2066 on the same route90.3%
- JetBlue Airways 1883 on the same route87.7%
- JetBlue Airways 2783 on the same route62.6%
- Delta Air Lines 2118 on the same route88.3%
- Boston Logan International (BOS) delay statistics
- Raleigh-Durham International (RDU) 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.