Route profile
IAH→DCA
Flight reliability, delays and best times to fly from Houston to Washington, 1,208 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 29% of comparable major US routes (4,598 compared)
Calculated from 7,840 flights. How this is calculated · What counts as on time
IAH → DCA arrives on time 76.3% of the time; the return trip, DCA → IAH, arrives on time 81.9% of the time, a 5.6-point gap between the two directions of the same city pair.
IAH → DCA spends 27.3 minutes on the ground on a 1,208-mile trip: 21.4 minutes from pushback to wheels-up at IAH and 5.9 minutes from touchdown to gate at DCA.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
This route has stayed remarkably steady year over year, a smaller swing than 97% of 5,368 comparable routes.
75.0% on time over the most recent 12 months (2025-08 to 2026-07), against 74.8% in the 12 months before (2024-08 to 2025-07), virtually unchanged.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 5,368 in the comparison.
What sets this route apart
Where IAH to DCA differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
IAH to DCA struggles most at 5 PM: 59.0% of its flights scheduled then arrive on time, 8.9 points behind the 67.9% on routes of similar length at the same hour. Against all other routes the gap is 10.8 points.
IAH to DCA is at its best against routes of similar length for flights scheduled at 12 PM: 82.0% arrive on time, 4.1 points ahead of the 77.9% those routes manage at that hour.
January is kinder to IAH to DCA than to routes of similar length: 83.8% on time against 77.3%, 6.5 points better. Against all other routes the gap is 4.7 points.
In February, IAH to DCA runs 6.4 points below routes of similar length, 74.1% on time to 80.5%. Against all other routes the gap is 7.4 points.
United Airlines’ flights on IAH to DCA arrive on time 76.6% of the time, 4.9 points below the 81.5% it manages on its routes of similar length. Against all other routes the gap is 3.3 points.
IAH to DCA against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 5 PM departures | 59.0% | routes of similar length | 67.9% | −8.9 pts | 234 here, 119,650 there |
| Hour: 12 PM departures | 82.0% | routes of similar length | 77.9% | +4.1 pts | 440 here, 126,750 there |
| Month: January | 83.8% | routes of similar length | 77.3% | +6.5 pts | 597 here, 151,285 there |
| Month: February | 74.1% | routes of similar length | 80.5% | −6.4 pts | 618 here, 148,095 there |
| Airline: United Airlines | 76.6% | routes of similar length | 81.5% | −4.9 pts | 6,764 here, 259,233 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,208 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
Why IAH → DCA flights are cancelled
July 2023 – July 2026
IAH → DCA cancelled 142 of 7,840 scheduled flights — about 1 in every 55. The reason filed most often was extreme weather, 57.0% of the cancellations coded on this route — about 1 in every 97 scheduled flights.
Share of cancellations
Of 142 cancelled departures carrying a reason code.
What each reason means
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
81 cancellations, 57.0% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
31 cancellations, 21.8% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
30 cancellations, 21.1% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
142 coded cancellations were recorded on IAH → DCA; the section appears from 50.
When it goes wrong
July 2023 – July 2026
54 min late
against a median of 6 min early
IAH → DCA has an average that understates its risk: a typical arrival is 6 min early, but the worst tenth are 60 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 7,840 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at DCA after arriving from IAH.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 37% | Likely to miss |
| 45 min | 23% | High risk |
| 60 min | 16% | High risk |
| 90 min | 8.9% | Some risk |
| 120 min | 5.4% | Some risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.81% of the time and diverts 0.55% of the time, which a late arrival never shows up in.
Chance of missing is the share of 7,655 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 54 minutes late (90th-percentile gate arrival delay), over 7,840 operations.
Any other layover length: connection checker.
Best time to fly
IAH → DCA flights departing 5–9 AM arrived on time 90.6% of the time, against 67.4% for 3–6 PM departures, a gap of 23.2 percentage points.
By departure window
By departure hour
- 12 AM to 5 AM: too few flights to score
- 6 AM: 86.8% on time from 250 flights
- 7 AM: 91.8% on time from 1,113 flights
- 8 AM: too few flights to score
- 9 AM: 81.9% on time from 1,037 flights
- 10 AM: 80.6% on time from 136 flights
- 11 AM: 76.5% on time from 679 flights
- 12 PM: 82.0% on time from 444 flights
- 1 PM: too few flights to score
- 2 PM: 73.4% on time from 887 flights
- 3 PM: too few flights to score
- 4 PM: 69.1% on time from 1,129 flights
- 5 PM: 59.0% on time from 249 flights
- 6 PM: 69.3% on time from 1,111 flights
- 7 PM: 67.3% on time from 695 flights
- 8 PM to 11 PM: too few flights to score
Why IAH → DCA runs late
July 2023 – July 2026
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for IAH → DCA. Only delays of 15 minutes or more are attributed. What the five causes mean
Late-arriving aircraft is the largest cause on IAH → DCA, at 36.9%: flights here mostly leave late because the plane came in late, and the day shows it: 5–9 AM departures arrived on time 90.6% of the time and 3–6 PM departures 67.4%.
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 6,894 | 76.6% | 1.33% | -6 min | 8.8% |
| Republic Airways | 513 | 75.9% | 4.87% | -7 min | 7.2% |
| PSA Airlines | 360 | 68.5% | 6.67% | 0 min | 16.2% |
United Airlines flew 88.8% of the 7,767 flights listed. PSA Airlines cancelled 6.67% of its flights here against 1.33% for United Airlines.
United Airlines arrived on time 8.1 percentage points more often than PSA Airlines on this route.
Weekly and seasonal patterns
By day of week
Tuesday is historically the most reliable day and Friday the least, a gap of 7.2 percentage points.
By month
- Jan: 83.8%
- Feb: 74.1%
- Mar: 75.9%
- Apr: 80.2%
- May: 71.5%
- Jun: 66.0%
- Jul: 66.3%
- Aug: 73.2%
- Sep: 80.2%
- Oct: 82.8%
- Nov: 81.2%
- Dec: 82.2%
June is historically the weakest month and January the strongest, a spread of 17.8 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 78.4% from 166 flights
- August 2023: 86.5% from 172 flights
- September 2023: 75.4% from 169 flights
- October 2023: 88.9% from 181 flights
- November 2023: 87.0% from 193 flights
- December 2023: 85.0% from 180 flights
- January 2024: 79.0% from 184 flights
- February 2024: 85.9% from 193 flights
- March 2024: 80.1% from 196 flights
- April 2024: 77.8% from 176 flights
- May 2024: 65.4% from 169 flights
- June 2024: 75.0% from 160 flights
- July 2024: 64.4% from 167 flights
- August 2024: 72.6% from 170 flights
- September 2024: 84.5% from 171 flights
- October 2024: 84.6% from 182 flights
- November 2024: 82.6% from 196 flights
- December 2024: 78.2% from 179 flights
- January 2025: 88.6% from 177 flights
- February 2025: 57.0% from 176 flights
- March 2025: 75.6% from 196 flights
- April 2025: 82.7% from 202 flights
- May 2025: 72.3% from 205 flights
- June 2025: 62.4% from 194 flights
- July 2025: 58.6% from 207 flights
- August 2025: 62.6% from 207 flights
- September 2025: 80.5% from 272 flights
- October 2025: 77.9% from 291 flights
- November 2025: 75.9% from 270 flights
- December 2025: 83.0% from 273 flights
- January 2026: 84.0% from 282 flights
- February 2026: 76.8% from 259 flights
- March 2026: 73.2% from 289 flights
- April 2026: 79.8% from 283 flights
- May 2026: 74.4% from 289 flights
- June 2026: 63.2% from 280 flights
- July 2026: 65.8% from 284 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 75.0% against 74.8% in the 12 months before — broadly unchanged.
Data and methodology
Calculated by FlyerIntel from 7,840 IAH → DCA flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed