Route reliability record
AUS→IAD
Austin to Washington
- Flights
- 1,019
- Period
- September 2025 to August 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 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 1,019 AUS to IAD flights, with a median arrival 7 minutes early.
Best time to fly AUS to IAD: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 93.5% of the time and Tuesday flights 92.4%, against 89.2% for the route overall.
Set against the rest of the country, this route's record is 12 points better than the US average of 77.3%. That gap is worth roughly 119 fewer late arrivals for every thousand flights.
Key figures
On time
89.2%
Arrivals under 15 minutes late, of 1,010 completed flights
Avg delay
103 min
Across delayed arrivals only, not all flights
Cancelled
0.79%
National rate is 1.89%
Best carrier
United
90.1% on time across 988 flights
These figures cover 1,019 flights between September 2025 and August 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.
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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 | 988 | 90.1% | 91 min | 0.81% | A+ |
| Republic Airwaysthin sample | 11 | 81.8% | 904 min | 0.00% | B+ |
| Allegiant Airthin sample | 20 | 50.0% | 60 min | 0.00% | F+ |
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.
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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 | 89.4% | 90.1% | 0.81% | 5am–8am, Tue (route) | UA 525 07:15 |
| 2. AUS → BWIAustin to Baltimore | Southwest Airlines | 74.7% | 76.0% | 1.65% | 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 22 points, against half a point between the best and worst carrier.
- 5am–8am341 flights93.5%
- 8am–11am24 flights—
- 11am–2pm332 flights89.7%
- 2pm–5pm60 flights71.7%
- 5pm–8pm262 flights86.2%
- 8pm–5am—
Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.5% of the time, against 71.7% for the afternoon window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 341 flights scheduled in it.
Explore
Filter AUS to IAD by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On AUS to IAD, the best departure window is 5am–8am at 93.5% on time and the worst is 2pm–5pm at 71.7%, a wide gap of 21.8 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.5%
- 8–11am—
- 11am–2pm89.7%
- 2–5pm71.7%
- 5–8pm86.2%
- 8pm–5am—
best all US flightsScale 60% to 100%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 16 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 81.6% on time, 16 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 92.4% on time and Friday the weakest at 86.1%, a spread of 6 points.
Delay causes
Why this route gets delayed
Carrier accounts for 48% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 48%Carrier
- 31%Late-arriving aircraft
- 20%National Airspace System
- 1%Extreme weather
The largest share of delay minutes, 48%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 5,446 of the 11,000 delay minutes reported here. The split is drawn from 11,276 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 93.5% on time here.
Cancellations are rare at 0.79%, 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 actually costs
Badly late arrivals are rare here: only 4.5% land an hour or more behind schedule, against 8.3% 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.
The return leg is a different operation and performs like one: it runs 83.8% on time across 1,018 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. 1,019 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. 1,019 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 89.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 1,010 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 10.8% of the 1,019 flights in this analysis, against 22.7% nationally. Delayed flights are late by close to two hours on average.
How reliable is AUS to IAD compared with the rest of the country?
89.2% of flights arrive on time here against a national 77.3%, 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 5am–8am departure window is the strongest at 93.5% on time. The 2pm–5pm window is the weakest at 71.7%, 22 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 81.6% on time, compared with 97.3% in September. Across the year that is 16 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 route78.9%
- ATL to IAD, a related route76.4%
- AUS to DFW, a related route74.9%
- United Airlines on-time record90.1%
- Republic Airways on-time record81.8%
- Allegiant Air on-time record50.0%
- The most punctual routes in the US, and the least
- The best time of day to fly, according to 7.05 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.