Flight number record
DL 378
Delta Air Lines · Atlanta to Washington
- Route
- ATL → DCA
- Departs
- 20:55
- Flights
- 263
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 378, check with Delta Air Lines.
DL 378 draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 263 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.3%, so DL 378 runs 12 points behind the country as a whole. Across a thousand flights that is about 115 extra late arrivals.
Key figures
On time
65.8%
Arrivals under 15 minutes late, of 257 completed flights
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
2.28%
National rate is 1.89%
1 hour+ late
11.3%
National rate is 8.3%
These figures cover 263 flights between September 2025 and August 2026. Beyond the headline rate, 11.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 378 flies
DL 378 flies ATL to DCA without a single fixed slot. Its most common scheduled departure was 20:55, used on 116 of 263 flights, with 20:59 (107 flights) next.
- Departs 20:55116 flights44.1%
- Departs 20:59107 flights40.7%
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 20:55 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and DL 378 runs 4 points worse at 65.8%. 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 378 next to ATL to DCA
Every carrier on ATL to DCA combined arrived on time 68.7% of the time across 6,798 flights, so DL 378 is 3 points behind it. Delta flew 3,850 flights on the same city pair under all its flight numbers, including this one, and those ran 66.7% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 15 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 378thin sample | 263 | 65.8% | 66 min | 2.28% | C |
| All Delta Air Lines on ATL–DCA | 3,850 | 66.7% | 60 min | 2.44% | C |
| All carriers on ATL–DCA | 6,798 | 68.7% | 70 min | 3.43% | C− |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 378 quarter by quarter
DL 378 did not run the same all year. Its best quarter was Oct–Dec 2025 at 75.9% on time and its weakest Jul–Sep 2026 at 53.8%, a swing of 22 points on roughly 66 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 202522 flights—
- Oct–Dec 202555 flights75.9%
- Jan–Mar 202663 flights54.1%
- Apr–Jun 202670 flights69.1%
- Jul–Sep 202653 flights53.8%
Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, DL 378 did best on Monday at 78.4% on time and worst on Thursday at 54.2%. Each day rests on about 38 flights, so a gap of 24 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 378 runs when it is late
The 88 late arrivals split 29 under half an hour, 30 between 30 and 60 minutes, and 29 an hour or more.
- 15+ min early20 flights7.8%
- Within 15 min149 flights58.0%
- 15–29 min late29 flights11.3%
- 30–59 min late30 flights11.7%
- 1–2 hours late20 flights7.8%
- 2+ hours late9 flights3.5%
Scale runs 0% to 100%.
Share of 257 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 81 departures that left 15 minutes late or more, only 9 made it up before arrival. In the other direction, 16 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 DCA.
The worst days
Worst days for DL 378
The latest arrival of the period was on 11 June 2026, 18 hours 25 minutes behind schedule; most of its delay minutes were filed as extreme weather. The five worst days are spread across June, November, July and March, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 June 2026 | 18 hours 25 minutes | Extreme weather |
| 29 June 2026 | 2 hours 45 minutes | Carrier |
| 7 November 2025 | 2 hours 38 minutes | National Airspace System |
| 21 July 2026 | 2 hours 32 minutes | National Airspace System |
| 6 March 2026 | 2 hours 28 minutes | Extreme weather |
Delay causes
Why DL 378 runs late
National Airspace System accounts for 42% of the 5,763 delay minutes carriers reported here, and the remaining four split what is left.
- 42%National Airspace System
- 27%Carrier
- 20%Extreme weather
- 10%Late-arriving aircraft
Extreme weather accounts for 20% 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 3.4 times the usual weather exposure. The split is drawn from 5,763 delay minutes reported on DL 378.
Cancellations sit at 2.28% against a national 1.89%, which is ordinary. Diversions add another 0.00%.
Connections and routes
What a delay on this flight costs
11.3% 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 547 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 two other city pairs in the data, including DCA to ATL (1) and DTW to RSW (1), but none flew often enough under DL 378 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ATL to DCA only.
One caution: this is a thin sample. 263 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 378
For a booking, read DL 378 as 65.8% on time with 2.28% cancelled over 263 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- ATL to DCA, every carrier and departure
- DCA to ATL, the return direction
- Delta Air Lines 360 on the same route69.7%
- Delta Air Lines 537 on the same route67.3%
- Delta Air Lines 380 on the same route80.4%
- Delta Air Lines 325 on the same route58.3%
- Delta Air Lines 926 on the same route84.1%
- Delta Air Lines 727 on the same route53.3%
- Hartsfield-Jackson Atlanta International (ATL) delay statistics
- Ronald Reagan Washington National (DCA) 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
- How often a connection fails at the major US hubs
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.