Flight number record
DL 2646
Delta Air Lines · Boston to Chicago
- Route
- BOS → ORD
- Departs
- 16:05
- Flights
- 262
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 2646, check with Delta Air Lines.
DL 2646 draws a D−. Roughly one flight in three 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 262 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.6%, so DL 2646 runs 17 points behind the country as a whole. Across a thousand flights that is about 173 extra late arrivals.
Key figures
On time
60.3%
Arrivals under 15 minutes late, of 247 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
4.20%
National rate is 1.81%
1 hour+ late
17.0%
National rate is 8.1%
These figures cover 262 flights between July 2025 and June 2026. Beyond the headline rate, 17.0% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Schedule
When DL 2646 flies
DL 2646 flies BOS to ORD without a single fixed slot. Its most common scheduled departure was 16:05, used on 90 of 262 flights, with 16:15 (42 flights) and 16:25 (31 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 16:0590 flights34.4%
- Departs 16:1542 flights16.0%
- Departs 16:2531 flights11.8%
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 16:05 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 72.4%, and DL 2646 runs 12 points worse at 60.3%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
Against the route
DL 2646 next to BOS to ORD
Every carrier on BOS to ORD combined arrived on time 72.7% of the time across 7,637 flights, so DL 2646 is 12 points behind it. Delta flew 962 flights on the same city pair under all its flight numbers, including this one, and those ran 65.2% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 21 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 2646thin sample | 262 | 60.3% | 79 min | 4.20% | D− |
| All Delta Air Lines on BOS–ORD | 962 | 65.2% | 75 min | 3.12% | C− |
| All carriers on BOS–ORD | 7,637 | 72.7% | 84 min | 2.91% | C |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | 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 Oct–Dec 2025 at 54.5%, a swing of 16 points on roughly 87 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 flights56.2%
- Oct–Dec 202570 flights54.5%
- Jan–Mar 202621 flights—
- Apr–Jun 202679 flights70.3%
Scale runs 45% to 75%. Rows with fewer than 30 flights show a dash.
By weekday, DL 2646 did best on Friday at 72.5% on time and worst on Monday at 51.4%. Each day rests on about 37 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 2646 runs late
One category carries most of the weight here. National Airspace System accounts for 44% of the 7,698 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.
- 44%National Airspace System
- 38%Late-arriving aircraft
- 18%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. That is a cascade, and cascades start small and grow through the day. Across 7,698 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 7,698 delay minutes reported on DL 2646.
Cancellations run at 4.20%, against 1.81% nationally. That is about one flight in 25 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 17.0% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum 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. 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.
The same number turns up on one other city pair in the data, including ORD to BOS (162), 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. 262 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: 4.20% of its 262 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 route52.3%
- United Airlines 1732 on the same route84.5%
- United Airlines 1414 on the same route94.2%
- United Airlines 1015 on the same route48.8%
- JetBlue Airways 311 on the same route84.3%
- Delta Air Lines 2570 on the same route80.0%
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.