Flight number record
DL 378
Delta Air Lines · Atlanta to Washington
- Route
- ATL → DCA
- Departs
- 20:59
- Flights
- 262
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s DL 378, check with Delta Air Lines.
DL 378 draws a D. About 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 2 minutes late.
The national on-time rate over the same period is 77.6%, so DL 378 runs 13 points behind the country as a whole. Across a thousand flights that is about 134 extra late arrivals.
Key figures
On time
64.2%
Arrivals under 15 minutes late, of 254 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
2.67%
National rate is 1.81%
1 hour+ late
15.4%
National rate is 8.1%
These figures cover 262 flights between July 2025 and June 2026. Beyond the headline rate, 15.4% 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 378 flies
DL 378 flies ATL to DCA without a single fixed slot. Its most common scheduled departure was 20:59, used on 129 of 262 flights, with 20:55 (93 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 20:59129 flights49.2%
- Departs 20:5593 flights35.5%
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 20:59 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and DL 378 runs 6 points worse at 64.2%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
DL 378 next to ATL to DCA
Every carrier on ATL to DCA combined arrived on time 70.1% of the time across 6,812 flights, so DL 378 is 6 points behind it. Delta flew 3,838 flights on the same city pair under all its flight numbers, including this one, and those ran 67.3% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 17 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 378thin sample | 262 | 64.2% | 76 min | 2.67% | D |
| All Delta Air Lines on ATL–DCA | 3,838 | 67.3% | 60 min | 2.58% | C |
| All carriers on ATL–DCA | 6,812 | 70.1% | 70 min | 3.32% | C− |
| Delta Air Lines, whole network | 1,038,570 | 81.6% | 71 min | 1.62% | 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 Jan–Mar 2026 at 54.1%, 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 202574 flights59.2%
- Oct–Dec 202555 flights75.9%
- Jan–Mar 202663 flights54.1%
- Apr–Jun 202670 flights69.1%
Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.
By weekday, DL 378 did best on Monday at 77.6% on time and worst on Thursday at 48.9%. Each day rests on about 37 flights, so a gap of 29 points is worth noticing but could still narrow in another year.
Delay causes
Why DL 378 runs late
One category carries most of the weight here. National Airspace System accounts for 44% of the 6,867 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
- 24%Carrier
- 18%Extreme weather
- 15%Late-arriving aircraft
Extreme weather accounts for 18% 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 6,867 delay minutes reported on DL 378.
Cancellations run at 2.67%, against 1.81% nationally. That is about one flight in 40 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. 15.4% 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 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. 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 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. 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 378
For a booking, the cancellation rate is the figure to plan around on DL 378: 2.67% 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
- ATL to DCA, every carrier and departure
- DCA to ATL, the return direction
- Delta Air Lines 737 on the same route81.1%
- Delta Air Lines 360 on the same route70.8%
- Delta Air Lines 380 on the same route79.7%
- Delta Air Lines 537 on the same route68.9%
- Delta Air Lines 926 on the same route83.3%
- Delta Air Lines 325 on the same route58.3%
- 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
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.