Carrier route record
UADEN→DCA
United Airlines · Denver to Washington
- Flights
- 365
- Period
- July 2025 to June 2026
- Share of route
- 27%
- Carriers
- 2
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on DEN to DCA earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 365 flights, with a median arrival 9 minutes early.
Set against the rest of the country, United's DEN to DCA record is 11 points better than the US average of 77.6%. That gap is worth roughly 111 fewer late arrivals for every thousand flights.
Key figures
On time
88.7%
Arrivals under 15 minutes late, of 362 completed flights
Avg delay
61 min
Across delayed arrivals only, not all flights
Cancelled
0.27%
National rate is 1.81%
Whole route
81.2%
Every carrier on DEN to DCA, 1,351 flights
These figures cover 365 flights between July 2025 and June 2026. The median arrival is 9 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
United against every carrier on DEN to DCA
United flew 365 of the 1,351 flights on DEN to DCA, about 27% of it. Its 88.7% on time is 8 points better than the route as a whole, which runs 81.2%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 88.7% to Frontier at 78.4%.
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 |
|---|---|---|---|---|---|
| United Airlines (this page) | 365 | 88.7% | 61 min | 0.27% | A+ |
| Frontier Airlines | 986 | 78.4% | 76 min | 0.81% | B+ |
Departure window
When United 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 365 flights.
There are not enough flights in each departure window to split United's DEN to DCA record by time of day without the percentages moving on noise. The headline rate of 88.7% is the reliable figure here.
Across the year
United on DEN to DCA through the year
May is the best month on the calendar at 96.8% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. January was the busiest month here, with 31 flights.
Across the week, Tuesday is the strongest day at 98.1% on time and Friday the weakest at 80.8%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 2,479 reported delay minutes.
- 40%National Airspace System
- 33%Late-arriving aircraft
- 27%Carrier
40% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 993 minutes out of 2,479, against a national NAS share of 21%. The split is drawn from 2,479 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 88.7% on time here.
Cancellations are rare at 0.27%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
Badly late arrivals are rare here: only 3.6% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,476 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 78.8% on time across 365 flights, 10 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 10 points of difference.
One caution: this is a thin sample. 365 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 United on DEN to DCA
Put together: treat all of this as provisional. 365 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 88.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 362 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to DCA, every carrier
- United on DCA to DEN, the return leg
- Frontier Airlines on DEN to DCA78.4%
- United Airlines network-wide record
- Denver International (DEN) delay statistics
- Ronald Reagan Washington National (DCA) delay statistics
- Why the first flight of the morning is statistically safest
- Worst months to fly in the US, ranked by the data
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.