Route reliability record
AUS→IAD
Austin to Washington
- Flights
- 1,049
- Period
- July 2025 to June 2026
- Distance
- 1,297 mi
- Carriers
- 3
This route earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 12 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 1,049 AUS to IAD flights, with a median arrival 7 minutes early.
Best time to fly AUS to IAD: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 94.3% of the time and Tuesday flights 92.1%, against 89.1% for the route overall.
Set against the rest of the country, this route's record is 12 points better than the US average of 77.6%. That gap is worth roughly 115 fewer late arrivals for every thousand flights.
Key figures
On time
89.1%
Arrivals under 15 minutes late, of 1,039 completed flights
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
0.76%
National rate is 1.81%
Best carrier
United
90.0% on time across 1,007 flights
These figures cover 1,049 flights between July 2025 and June 2026. The median arrival is 7 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
Which airline is most reliable on AUS to IAD
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 | 1,007 | 90.0% | 67 min | 0.79% | A+ |
| Republic Airwaysthin sample | 18 | 77.8% | 686 min | 0.00% | B+ |
| Allegiant Airthin sample | 24 | 62.5% | 55 min | 0.00% | D+ |
Flight by flight
Flights on AUS to IAD
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.
Best ways to make this trip
The most reliable ways to fly Austin 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. 1 of the top 2 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. AUS → IADAustin to Washington | United Airlines | 89.3% | 90.0% | 0.79% | 8am–11am, Tue (route) | UA 525 07:15 |
| 2. AUS → BWIAustin to Baltimore | Southwest Airlines | 75.3% | 76.4% | 1.48% | 5am–8am, 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 19 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–8am346 flights93.5%
- 8am–11am36 flights94.3%
- 11am–2pm349 flights89.3%
- 2pm–5pm53 flights75.5%
- 5pm–8pm265 flights85.2%
- 8pm–5am—
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 94.3% of the time, against 75.5% for the afternoon window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 349 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 22 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.
July is the worst month at 75.8% on time, 22 points below September, the best at 97.3%. 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. September was the busiest month here, with 110 flights.
Across the week, Tuesday is the strongest day at 92.1% on time and Friday the weakest at 85.0%. 7 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 9,939 reported delay minutes.
- 38%Late-arriving aircraft
- 37%Carrier
- 23%National Airspace System
- 2%Extreme weather
38% 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 9,939 reported delay minutes here, that single category outweighs weather by 16 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 9,939 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 3,654 of the 9,939 delay minutes reported here.
Cancellations are rare at 0.76%, below the national 1.81% 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
Badly late arrivals are rare here: only 4.2% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,297 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 83.9% on time across 1,049 flights, 5 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 5 points of difference.
One caution: this is a thin sample. 1,049 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
Work out the risk of missing a connection in IAD after this flight
What to do with this
Booking this route
Put together: treat all of this as provisional. 1,049 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 89.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,039 completed flights over 12 months sit behind that.
Common questions
AUS to IAD questions
How often is AUS to IAD delayed?
About one flight in nine arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 10.9% of the 1,049 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is AUS to IAD compared with the rest of the country?
89.1% of flights arrive on time here against a national 77.6%, a difference of 12 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on AUS to IAD?
The 8am–11am departure window is the strongest at 94.3% on time. The 2pm–5pm window is the weakest at 75.5%, 19 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 July delays on AUS to IAD?
July is the weakest month at 75.8% on time, compared with 97.3% in September. Across the year that is 22 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
- IAD to AUS — the return legseparate record
- Austin-Bergstrom International (AUS) delay statistics
- Washington Dulles International (IAD) delay statistics
- AUS to DEN, a related route78.4%
- ATL to IAD, a related route76.5%
- AUS to DFW, a related route73.8%
- United Airlines on-time record90.0%
- Republic Airways on-time record77.8%
- Allegiant Air on-time record62.5%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. AUS to IAD and IAD to AUS 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.