Carrier route record
UADCA→DEN
United Airlines · Washington to Denver
- Flights
- 364
- Period
- September 2025 to August 2026
- Share of route
- 27%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on DCA to DEN lands a B+, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That rests on 364 flights, with a median arrival 6 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate United on DCA to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.4%
Arrivals under 15 minutes late, of 356 completed flights
Avg delay
87 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.89%
Whole route
78.2%
Every carrier on DCA to DEN, 1,347 flights
These figures cover 364 flights between September 2025 and August 2026. Beyond the headline rate, 9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
United against every carrier on DCA to DEN
United flew 364 of the 1,347 flights on DCA to DEN, about 27% of it. Its 78.4% on time is about level with the route as a whole at 78.2%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 78.4% to Frontier at 78.1%.
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)thin sample | 364 | 78.4% | 87 min | 0.55% | B+ |
| Frontier Airlines | 983 | 78.1% | 81 min | 1.02% | B |
Flight by flight
United flight numbers on DCA to DEN
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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 364 flights.
There are not enough flights in each departure window to split United's DCA to DEN record by time of day without the percentages moving on noise. The headline rate of 78.4% is the reliable figure here.
Across the year
United on DCA to DEN through the year
Delays peak in September, when the on-time rate falls to 70.0%. January is the strongest month at 90.0%. Moving a flexible trip across that boundary buys 20 points. January was the busiest month here, with 31 flights.
Across the week, Tuesday is the strongest day at 86.3% on time and Thursday the weakest at 68.0%, a spread of 18 points.
Arrival by arrival
How late United on DCA to DEN runs when it is late
United on DCA to DEN often beats the schedule: 95 of 356 completed flights, 27%, arrived 15 minutes or more early. The 77 late arrivals split 26 under half an hour, 19 between 30 and 60 minutes, and 32 an hour or more.
- 15+ min early95 flights26.7%
- Within 15 min184 flights51.7%
- 15–29 min late26 flights7.3%
- 30–59 min late19 flights5.3%
- 1–2 hours late14 flights3.9%
- 2+ hours late18 flights5.1%
Scale runs 0% to 100%.
Share of 356 completed flights by arrival against schedule.
17 of 65 late departures made up the time and arrived on time, 26% of them. In the other direction, 29 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 DEN.
The worst days
Worst days for United on DCA to DEN
The latest arrival of the period was on 11 June 2026, 14 hours 57 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 11 June 2026 | 14 hours 57 minutes | Carrier |
| 14 January 2026 | 6 hours 28 minutes | Late-arriving aircraft |
| 13 March 2026 | 5 hours 16 minutes | Carrier |
| 26 December 2025 | 4 hours 42 minutes | Carrier |
| 17 December 2025 | 4 hours 3 minutes | Late-arriving aircraft |
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 6,690 reported delay minutes.
- 35%National Airspace System
- 31%Carrier
- 29%Late-arriving aircraft
- 5%Extreme weather
35% 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 2,362 minutes out of 6,690, against a national NAS share of 21%. The split is drawn from 6,690 reported delay minutes.
Cancellations are rare at 0.55%, below the national 1.89% 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
9.0% 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 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.
The return leg is a different operation and performs like one: it runs 88.6% on time across 364 flights, 10 points above 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. 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 United on DCA to DEN
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 78.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 356 completed flights over 12 months sit behind that.
Related
Where to go next
- DCA to DEN, every carrier
- United on DEN to DCA, the return leg
- Frontier Airlines on DCA to DEN78.1%
- United Airlines network-wide record
- Ronald Reagan Washington National (DCA) delay statistics
- Denver International (DEN) delay statistics
- How often a connection fails at the major US hubs
- Connecting flights: how much buffer the data says you need
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.