Carrier route record

UADCA→DEN

United Airlines · Washington to Denver

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 DCA to DEN lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by close to two hours on average. That is a workable record, not a spotless one. That rests on 365 flights, with a median arrival 6 minutes early.

The US average over the same twelve months is 77.6%, 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.

On time

78.8%

Arrivals under 15 minutes late, of 359 completed flights

Avg delay

104 min

Across delayed arrivals only, not all flights

Cancelled

0.27%

National rate is 1.81%

Whole route

78.5%

Every carrier on DCA to DEN, 1,349 flights

These figures cover 365 flights between July 2025 and June 2026. Beyond the headline rate, 8.9% 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

United against every carrier on DCA to DEN

United flew 365 of the 1,349 flights on DCA to DEN, about 27% of it. Its 78.8% on time is about level with the route as a whole at 78.5%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 78.8% 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.

On-time performance by carrier on DCA to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines (this page)	365	78.8%	104 min	0.27%	B+
Frontier Airlines	984	78.4%	80 min	0.91%	B+

Flight by flight

United flight numbers on DCA to DEN

UA 74616:1178.8% · 364 flights

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 DCA to DEN record by time of day without the percentages moving on noise. The headline rate of 78.8% is the reliable figure here.

Across the year

United on DCA to DEN through the year

Darker means more delays. Figures are on-time percentages.January best, September worst

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, Saturday is the strongest day at 90.4% on time and Thursday the weakest at 70.0%. 20 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 7,899 reported delay minutes.

Carrier
35%
Late-arriving aircraft
32%
National Airspace System
27%
Extreme weather
6%

The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,734 of the 7,899 delay minutes reported here. The split is drawn from 7,899 reported delay minutes.

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

8.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last close to two hours, which a normal layover absorbs.

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 88.7% on time across 365 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. 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 DCA to DEN

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 78.8% 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.

Where to go next

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.

Key figures