Carrier route record
UADCA→IAH
United Airlines · Washington to Houston
- Flights
- 2,413
- Period
- July 2025 to June 2026
- Share of route
- 75%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on DCA to IAH lands a B+, 6 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 2,413 flights, with a median arrival 15 minutes early.
Set against the rest of the country, United's DCA to IAH record is 6 points better than the US average of 77.6%. That gap is worth roughly 62 fewer late arrivals for every thousand flights.
Key figures
On time
83.8%
Arrivals under 15 minutes late, of 2,386 completed flights
Avg delay
95 min
Across delayed arrivals only, not all flights
Cancelled
0.91%
National rate is 1.81%
Whole route
81.4%
Every carrier on DCA to IAH, 3,200 flights
These figures cover 2,413 flights between July 2025 and June 2026. The median arrival is 15 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 DCA to IAH
United flew 2,413 of the 3,200 flights on DCA to IAH, most of the route. Its 83.8% on time is 2 points better than the route as a whole, which runs 81.4%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 83.8% to PSA at 70.1%. One 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 |
|---|---|---|---|---|---|
| United Airlines (this page) | 2,413 | 83.8% | 95 min | 0.91% | B+ |
| Republic Airways | 511 | 75.7% | 56 min | 5.09% | B− |
| PSA Airlinesthin sample | 276 | 70.1% | 73 min | 5.43% | C− |
Flight by flight
United flight numbers on DCA to IAH
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 40 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am354 flights92.8%
- 8am–11am363 flights92.7%
- 11am–2pm728 flights87.9%
- 2pm–5pm588 flights73.7%
- 5pm–8pm111 flights52.7%
- 8pm–5am269 flights83.8%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 52.7% on time, against 92.8% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 11am–2pm window is the busiest, with 728 flights scheduled in it.
Across the year
United on DCA to IAH through the year
June is the worst month at 72.3% on time, 22 points below February, the best at 94.6%. 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. March was the busiest month here, with 209 flights.
Across the week, Tuesday is the strongest day at 88.3% on time and Friday the weakest at 79.0%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 43% of the 37,000 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.
- 43%Late-arriving aircraft
- 26%National Airspace System
- 26%Carrier
- 4%Extreme weather
- 0%Security
43% 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 37,000 reported delay minutes here, that single category outweighs weather by 10 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 36,614 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 92.8% on time here.
Cancellations sit at 0.91% against a national 1.81%, which is ordinary. Diversions add another 0.21%.
Connections and stage length
What a delay here costs
7.4% 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 an hour and a half, which a normal layover absorbs.
The 1,208 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 75.2% on time across 2,413 flights, 9 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 9 points of difference.
The sample behind these figures is 2,413 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.
What to do with this
Booking United on DCA to IAH
Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 94.6% on time and June 72.3%, a swing of 22 points. If the dates move at all, move them out of June before you think about anything else. 2,386 completed flights over 12 months sit behind that.
Related
Where to go next
- DCA to IAH, every carrier
- United on IAH to DCA, the return leg
- Republic Airways on DCA to IAH75.7%
- PSA Airlines on DCA to IAH70.1%
- United Airlines network-wide record
- Ronald Reagan Washington National (DCA) delay statistics
- George Bush Intercontinental (IAH) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.