Carrier route record
UADCA→IAH
United Airlines · Washington to Houston
- Flights
- 2,384
- Period
- September 2025 to August 2026
- Share of route
- 72%
- Carriers
- 3
Historical statistics for September 2025 to August 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 77.3%. 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 rests on 2,384 flights. The strongest carrier on the route with a full sample, Republic Airways, flew 511 at 75.7% on time.
Set against the rest of the country, United's DCA to IAH record is 6 points better than the US average of 77.3%. That gap is worth roughly 62 fewer late arrivals for every thousand flights.
Key figures
On time
83.5%
Arrivals under 15 minutes late, of 2,361 completed flights
Avg delay
85 min
Across delayed arrivals only, not all flights
Cancelled
0.80%
National rate is 1.89%
Whole route
80.3%
Every carrier on DCA to IAH, 3,333 flights
These figures cover 2,384 flights between September 2025 and August 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.
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Carrier by carrier
United against every carrier on DCA to IAH
United flew 2,384 of the 3,333 flights on DCA to IAH, most of the route. Its 83.5% on time is 3 points better than the route as a whole, which runs 80.3%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 83.5% to PSA at 66.6%.
The choice of carrier is not cosmetic here. Republic Airways arrives on time 75.7% of the time; PSA Airlines manages 66.6%. Sample sizes sit next to every figure, because a two-point gap across 438 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 2,384 | 83.5% | 85 min | 0.80% | B+ |
| Republic Airways | 511 | 75.7% | 56 min | 5.09% | B− |
| PSA Airlines | 438 | 66.6% | 83 min | 7.31% | C− |
PSA Airlines cancels 7.3% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Flight by flight
United flight numbers on DCA to IAH
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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 35 points, against 9 points between the best and worst carrier.
- 5am–8am353 flights92.8%
- 8am–11am362 flights90.8%
- 11am–2pm723 flights87.8%
- 2pm–5pm571 flights73.2%
- 5pm–8pm158 flights57.7%
- 8pm–5am217 flights87.9%
Scale runs 50% to 100%.
The 5pm–8pm window is where this operation falls apart: 57.7% 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 723 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, Wednesday is the strongest day at 86.0% on time and Monday the weakest at 80.6%, a spread of 5 points.
Arrival by arrival
How late United on DCA to IAH runs when it is late
United on DCA to IAH often beats the schedule: 1,217 of 2,361 completed flights, 52%, arrived 15 minutes or more early. The 389 late arrivals split 110 under half an hour, 102 between 30 and 60 minutes, and 177 an hour or more.
- 15+ min early1,217 flights51.5%
- Within 15 min755 flights32.0%
- 15–29 min late110 flights4.7%
- 30–59 min late102 flights4.3%
- 1–2 hours late96 flights4.1%
- 2+ hours late81 flights3.4%
Scale runs 0% to 100%.
Share of 2,361 completed flights by arrival against schedule.
79 of 379 late departures made up the time and arrived on time, 21% of them. 89 flights left on time and still arrived late.
The worst days
Worst days for United on DCA to IAH
The latest arrival of the period was on 17 March 2026, 16 hours 11 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 |
|---|---|---|
| 17 March 2026 | 16 hours 11 minutes | Carrier |
| 12 June 2026 | 10 hours 55 minutes | Late-arriving aircraft |
| 10 April 2026 | 10 hours 5 minutes | Carrier |
| 13 March 2026 | 8 hours 27 minutes | Late-arriving aircraft |
| 12 June 2026 | 8 hours 11 minutes | Carrier |
Delay causes
Why United runs late on this route
Late-arriving aircraft accounts for 46% of the 33,000 delay minutes carriers reported here, and the remaining four split what is left.
- 46%Late-arriving aircraft
- 28%National Airspace System
- 24%Carrier
- 3%Extreme weather
- 0%Security
46% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 33,000 reported delay minutes here, that single category outweighs weather by 17 to one. The split is drawn from 33,113 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 are rare at 0.80%, 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
7.5% 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 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.
The return leg is a different operation and performs like one: it runs 76.7% on time across 2,385 flights, 7 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 7 points of difference.
The sample behind these figures is 2,384 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. 2,361 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 IAH66.6%
- 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 7.05 million flight records
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.