Flight number record
DL 2646
Delta Air Lines · Boston to Chicago
- Route
- BOS → ORD
- Departs
- 16:15
- Flights
- 259
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 2646, check with Delta Air Lines.
DL 2646 draws a D−. Roughly one flight in two arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 259 flights, with a median arrival 3 minutes late.
The national on-time rate over the same period is 77.3%, so DL 2646 runs 18 points behind the country as a whole. Across a thousand flights that is about 180 extra late arrivals.
Key figures
On time
59.3%
Arrivals under 15 minutes late, of 243 completed flights
Avg delay
78 min
Across delayed arrivals only, not all flights
Cancelled
5.41%
National rate is 1.89%
1 hour+ late
16.9%
National rate is 8.3%
These figures cover 259 flights between September 2025 and August 2026. Beyond the headline rate, 16.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 2646 flies
DL 2646 flies BOS to ORD without a single fixed slot. Its most common scheduled departure was 16:15, used on 70 of 259 flights, with 16:05 (59 flights) and 16:25 (31 flights) next.
- Departs 16:1570 flights27.0%
- Departs 16:0559 flights22.8%
- Departs 16:2531 flights12.0%
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 16:15 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 2646 runs 13 points worse at 59.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
DL 2646 next to BOS to ORD
Every carrier on BOS to ORD combined arrived on time 71.9% of the time across 7,860 flights, so DL 2646 is 13 points behind it. Delta flew 981 flights on the same city pair under all its flight numbers, including this one, and those ran 63.7% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 22 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2646thin sample | 259 | 59.3% | 78 min | 5.41% | D− |
| All Delta Air Lines on BOS–ORD | 981 | 63.7% | 75 min | 3.47% | D− |
| All carriers on BOS–ORD | 7,860 | 71.9% | 87 min | 2.98% | C |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 2646 quarter by quarter
DL 2646 did not run the same all year. Its best quarter was Apr–Jun 2026 at 70.3% on time and its weakest Jul–Sep 2025 at 50.0%, a swing of 20 points on roughly 65 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 flights50.0%
- Oct–Dec 202570 flights54.5%
- Jan–Mar 202621 flights—
- Apr–Jun 202679 flights70.3%
- Jul–Sep 202659 flights54.5%
Scale runs 40% to 75%. Rows with fewer than 30 flights show a dash.
By weekday, DL 2646 did best on Friday at 69.2% on time and worst on Monday at 48.6%. Each day rests on about 37 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 2646 runs when it is late
The 99 late arrivals split 19 under half an hour, 39 between 30 and 60 minutes, and 41 an hour or more.
- 15+ min early50 flights20.6%
- Within 15 min94 flights38.7%
- 15–29 min late19 flights7.8%
- 30–59 min late39 flights16.0%
- 1–2 hours late23 flights9.5%
- 2+ hours late18 flights7.4%
Scale runs 0% to 100%.
Share of 243 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 92 departures that left 15 minutes late or more, only 8 made it up before arrival. In the other direction, 15 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 ORD.
The worst days
Worst days for DL 2646
The latest arrival of the period was on 2 August 2026, 4 hours 41 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. The five worst days are spread across August, November, March, October and July, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 2 August 2026 | 4 hours 41 minutes | National Airspace System |
| 9 November 2025 | 4 hours 31 minutes | Late-arriving aircraft |
| 22 March 2026 | 4 hours 27 minutes | Carrier |
| 14 October 2025 | 4 hours 26 minutes | Late-arriving aircraft |
| 28 July 2026 | 4 hours 24 minutes | National Airspace System |
Delay causes
Why DL 2646 runs late
National Airspace System accounts for 44% of the 7,679 delay minutes carriers reported here, and the remaining four split what is left.
- 44%National Airspace System
- 38%Late-arriving aircraft
- 17%Carrier
- 0%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 7,679 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 7,679 delay minutes reported on DL 2646.
Cancellations run at 5.41%, against 1.89% nationally. That is about one flight in twenty 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
16.9% 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 867 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 ORD to BOS (170), but none flew often enough under DL 2646 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to ORD only.
One caution: this is a thin sample. 259 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 2646
For a booking, the cancellation rate is the figure to plan around on DL 2646: 5.41% of its 259 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
- BOS to ORD, every carrier and departure
- ORD to BOS, the return direction
- United Airlines 2040 on the same route53.1%
- United Airlines 1414 on the same route93.6%
- United Airlines 1732 on the same route83.8%
- United Airlines 1349 on the same route86.0%
- United Airlines 1015 on the same route50.3%
- JetBlue Airways 311 on the same route79.1%
- Boston Logan International (BOS) delay statistics
- Chicago O'Hare International (ORD) 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.