Carrier route record
DLMIA→DCA
Delta Air Lines · Miami to Washington
- Flights
- 364
- Period
- July 2025 to June 2026
- Share of route
- 9%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on MIA to DCA sits in the middle of the pack with a B. Close to three flights in four arrive on time by the DOT's definition, 2 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 364 flights, with a median arrival 5 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Delta on MIA to DCA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
75.2%
Arrivals under 15 minutes late, of 359 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
1.10%
National rate is 1.81%
Whole route
74.7%
Every carrier on MIA to DCA, 3,962 flights
These figures cover 364 flights between July 2025 and June 2026. Beyond the headline rate, 10.9% 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.
Carrier by carrier
Delta against every carrier on MIA to DCA
Delta flew 364 of the 3,962 flights on MIA to DCA, about 9% of it. Its 75.2% on time is about level with the route as a whole at 74.7%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Envoy at 100.0% to Republic at 66.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 1 | 100.0% | — | 0.00% | A+ |
| Delta Air Lines (this page)thin sample | 364 | 75.2% | 75 min | 1.10% | B |
| American Airlines | 3,549 | 74.8% | 70 min | 2.28% | C |
| Republic Airwaysthin sample | 48 | 66.7% | 76 min | 0.00% | C+ |
Departure window
When Delta runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 364 flights.
There are not enough flights in each departure window to split Delta's MIA to DCA record by time of day without the percentages moving on noise. The headline rate of 75.2% is the reliable figure here.
Across the year
Delta on MIA to DCA through the year
July is the worst month at 60.0% on time, 37 points below October, the best at 96.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. January was the busiest month here, with 31 flights.
Across the week, Tuesday is the strongest day at 81.1% on time and Friday the weakest at 68.6%. 13 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 67% of the 6,646 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.
- 67%Late-arriving aircraft
- 19%National Airspace System
- 14%Carrier
- 1%Extreme weather
67% 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 6,646 reported delay minutes here, that single category outweighs weather by 67 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 6,646 reported delay minutes.
Cancellations sit at 1.10% against a national 1.81%, which is ordinary. Diversions add another 0.27%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.9% 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 919 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 return leg is a different operation and performs like one: it runs 67.2% on time across 364 flights, 8 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 8 points of difference.
One caution: this is a thin sample. 364 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 Delta on MIA to DCA
Put together: treat all of this as provisional. 364 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 75.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 359 completed flights over 12 months sit behind that.
Related
Where to go next
- MIA to DCA, every carrier
- Delta on DCA to MIA, the return leg
- American Airlines on MIA to DCA74.8%
- Delta Air Lines network-wide record
- Miami International (MIA) delay statistics
- Ronald Reagan Washington National (DCA) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.