Carrier route record
UAIAH→DCA
United Airlines · Houston to Washington
- Flights
- 2,385
- Period
- September 2025 to August 2026
- Share of route
- 71%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on IAH to DCA lands a B+, level with the national rate of 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 2,385 flights. The strongest carrier on the route with a full sample, Republic Airways, flew 513 at 75.9% on time.
The US average over the same twelve months is 77.3%, so there is little to separate United on IAH to DCA from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.7%
Arrivals under 15 minutes late, of 2,356 completed flights
Avg delay
69 min
Across delayed arrivals only, not all flights
Cancelled
0.67%
National rate is 1.89%
Whole route
75.3%
Every carrier on IAH to DCA, 3,337 flights
These figures cover 2,385 flights between September 2025 and August 2026. Beyond the headline rate, 8.6% 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 IAH to DCA
United flew 2,385 of the 3,337 flights on IAH to DCA, most of the route. Its 76.7% on time is about level with the route as a whole at 75.3%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 76.7% to PSA at 66.3%.
The choice of carrier is not cosmetic here. Republic Airways arrives on time 75.9% of the time; PSA Airlines manages 66.3%. Sample sizes sit next to every figure, because a two-point gap across 439 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 2,385 | 76.7% | 69 min | 0.67% | B+ |
| Republic Airways | 513 | 75.9% | 64 min | 4.87% | B− |
| PSA Airlines | 439 | 66.3% | 109 min | 8.20% | C− |
PSA Airlines cancels 8.2% 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 IAH to DCA
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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 27 points, against 10 points between the best and worst carrier.
- 5am–8am361 flights94.4%
- 8am–11am289 flights83.6%
- 11am–2pm363 flights78.8%
- 2pm–5pm434 flights73.6%
- 5pm–8pm601 flights67.2%
- 8pm–5am337 flights70.3%
Scale runs 60% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 94.4% of the time, against 67.2% for the evening 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 5pm–8pm window is the busiest, with 601 flights scheduled in it.
Across the year
United on IAH to DCA through the year
June is the worst month at 60.4% on time, 27 points below December, the best at 87.0%. 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 82.2% on time and Friday the weakest at 71.0%, a spread of 11 points.
Arrival by arrival
How late United on IAH to DCA runs when it is late
United on IAH to DCA often beats the schedule: 628 of 2,356 completed flights, 27%, arrived 15 minutes or more early. The 549 late arrivals split 148 under half an hour, 198 between 30 and 60 minutes, and 203 an hour or more.
- 15+ min early628 flights26.7%
- Within 15 min1,179 flights50.0%
- 15–29 min late148 flights6.3%
- 30–59 min late198 flights8.4%
- 1–2 hours late127 flights5.4%
- 2+ hours late76 flights3.2%
Scale runs 0% to 100%.
Share of 2,356 completed flights by arrival against schedule.
82 of 527 late departures made up the time and arrived on time, 16% of them. 104 flights left on time and still arrived late.
The worst days
Worst days for United on IAH to DCA
The latest arrival of the period was on 26 January 2026, 12 hours 54 minutes behind schedule; most of its delay minutes were filed as extreme weather. The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 26 January 2026 | 12 hours 54 minutes | Extreme weather |
| 26 January 2026 | 12 hours 4 minutes | Extreme weather |
| 15 June 2026 | 6 hours 37 minutes | Extreme weather |
| 18 June 2026 | 6 hours 31 minutes | Carrier |
| 16 March 2026 | 6 hours 27 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
National Airspace System accounts for 50% of the 38,000 delay minutes carriers reported here, and the remaining four split what is left.
- 50%National Airspace System
- 25%Late-arriving aircraft
- 17%Carrier
- 9%Extreme weather
50% 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 19,000 minutes out of 38,000, against a national NAS share of 21%. The split is drawn from 37,964 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 costs
8.6% 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 1,208 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 83.5% on time across 2,384 flights, 7 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 7 points of difference.
The sample behind these figures is 2,385 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 IAH to DCA
Put together: the calendar is the biggest lever here, not the carrier or the hour. December runs 87.0% on time and June 60.4%, a swing of 27 points. If the dates move at all, move them out of June before you think about anything else. 2,356 completed flights over 12 months sit behind that.
Related
Where to go next
- IAH to DCA, every carrier
- United on DCA to IAH, the return leg
- Republic Airways on IAH to DCA75.9%
- PSA Airlines on IAH to DCA66.3%
- United Airlines network-wide record
- George Bush Intercontinental (IAH) delay statistics
- Ronald Reagan Washington National (DCA) delay statistics
- 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
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.