Route reliability record
DEN→DCA
Denver to Washington
- Flights
- 1,347
- Period
- September 2025 to August 2026
- Distance
- 1,476 mi
- Carriers
- 2
This route lands a B+, 3 points 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 a little over an hour on average. That rests on 1,347 DEN to DCA flights, with a median arrival 11 minutes early.
Best time to fly DEN to DCA: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 92.6% of the time and Saturday flights 89.4%, against 80.6% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.6%
Arrivals under 15 minutes late, of 1,332 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
0.67%
National rate is 1.89%
Best carrier
Frontier
77.5% on time across 983 flights
These figures cover 1,347 flights between September 2025 and August 2026. The median arrival is 11 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.
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Carrier by carrier
Which airline is most reliable on DEN to DCA
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 Airlinesthin sample | 364 | 88.6% | 59 min | 0.27% | A+ |
| Frontier Airlines | 983 | 77.5% | 72 min | 0.81% | B+ |
Flight by flight
Flights on DEN to DCA
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Denver to Washington
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. DEN → IADDenver to Washington | United Airlines | 84.4% | 84.8% | 0.50% | 5am–8am, Wed | UA 1924 23:59 |
| 2. DEN → BWIDenver to Baltimore | United Airlines | 81.7% | 82.2% | 0.60% | 8am–11am, Wed | UA 1362 09:46 |
| 3. DEN → DCADenver to Washington | Frontier Airlines | 76.9% | 77.5% | 0.81% | 5am–8am, Sat | F9 686 07:35 |
| 4. DEN → BWIDenver to Baltimore | Southwest Airlines | 74.0% | 74.9% | 1.15% | 5am–8am, Wed | — |
| 5. DEN → IADDenver to Washington | Southwest Airlines | 67.0% | 67.7% | 1.01% | 8am–11am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 27 points, against half a point between the best and worst carrier.
- 5am–8am313 flights92.6%
- 8am–11am364 flights88.6%
- 11am–2pm315 flights75.6%
- 2pm–5pm355 flights66.0%
- 5pm–8pm—
- 8pm–5am—
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.6% of the time, against 66.0% for the afternoon window. That is 27 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 364 flights scheduled in it.
Explore
Filter DEN to DCA by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On DEN to DCA, the best departure window is 5am–8am at 92.6% on time and the worst is 2pm–5pm at 66.0%, a wide gap of 26.6 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.6%
- 8–11am88.6%
- 11am–2pm75.6%
- 2–5pm66.0%
- 5–8pm—
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 18 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 69.9% on time, 18 points below October, the best at 87.8%. 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 116 flights.
Across the week, Saturday is the strongest day at 89.4% on time and Friday the weakest at 76.2%, a spread of 13 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 49% of the 18,000 delay minutes carriers reported here, and the remaining four split what is left.
- 49%National Airspace System
- 24%Late-arriving aircraft
- 24%Carrier
- 3%Extreme weather
49% 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 8,873 minutes out of 18,000, against a national NAS share of 21%. The split is drawn from 18,161 reported delay minutes.
Cancellations are rare at 0.67%, 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 actually costs
7.1% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, 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.
The return leg runs 78.2% on time across 1,347 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,347 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in DCA after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 87.8% on time and August 69.9%, a swing of 18 points. If the dates move at all, move them out of August before you think about anything else. 1,332 completed flights over 12 months sit behind that.
Common questions
DEN to DCA questions
How often is DEN to DCA delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.4% of the 1,347 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
How reliable is DEN to DCA compared with the rest of the country?
80.6% of flights arrive on time here against a national 77.3%, a difference of 3 points in its favour. That is worth a B+ on this site's grading scale.
What time of day has the fewest delays on DEN to DCA?
The 5am–8am departure window is the strongest at 92.6% on time. The 2pm–5pm window is the weakest at 66.0%, 27 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are August delays on DEN to DCA?
August is the weakest month at 69.9% on time, compared with 87.8% in October. Across the year that is 18 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DCA to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Ronald Reagan Washington National (DCA) delay statistics
- United Airlines on DEN to DCA88.6%
- Frontier Airlines on DEN to DCA77.5%
- DEN to PHX, a related route75.6%
- BOS to DCA, a related route72.6%
- DEN to SLC, a related route78.2%
- United Airlines on-time record88.6%
- Frontier Airlines on-time record77.5%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. DEN to DCA and DCA to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.