Route reliability record
PIT→IAD
Pittsburgh to Washington
- Flights
- 1,266
- Period
- July 2025 to June 2026
- Distance
- 182 mi
- Carriers
- 2
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 11 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 1,266 PIT to IAD flights, of which Republic Airways flew 767 at 88.4% on time.
Best time to fly PIT to IAD: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 97.8% of the time and Saturday flights 97.5%, against 88.3% for the route overall.
Set against the rest of the country, this route's record is 11 points better than the US average of 77.6%. That gap is worth roughly 107 fewer late arrivals for every thousand flights.
Key figures
On time
88.3%
Arrivals under 15 minutes late, of 1,248 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
1.42%
National rate is 1.81%
Best carrier
Republic
88.4% on time across 767 flights
These figures cover 1,266 flights between July 2025 and June 2026. The median arrival is 11 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 PIT to IAD
The two carriers here are closely matched: half a point separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airways | 767 | 88.4% | 50 min | 1.83% | A |
| United Airlines | 499 | 88.1% | 72 min | 0.80% | A+ |
No carrier stands out. Republic tops the table at 88.4%, half a point clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on PIT 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 Pittsburgh 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. 2 of the top 4 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. PIT → IADPittsburgh to Washington | United Airlines | 87.4% | 88.1% | 0.80% | 8am–11am, Tue | — |
| 2. PIT → IADPittsburgh to Washington | Republic Airways | 86.8% | 88.4% | 1.83% | 5am–8am, Sat | YX 3679 06:15 |
| 3. PIT → BWIPittsburgh to Baltimore | Southwest Airlines | 84.4% | 85.5% | 1.30% | 8am–11am, Wed | — |
| 4. PIT → DCAPittsburgh to Washington | Republic Airways | 74.2% | 75.8% | 2.07% | 5am–8am, Sat | — |
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 24 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–8am360 flights97.8%
- 8am–11am263 flights93.5%
- 11am–2pm30 flights—
- 2pm–5pm284 flights73.6%
- 5pm–8pm—
- 8pm–5am329 flights86.3%
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 97.8% of the time, against 73.6% for the afternoon window. That is 24 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 360 flights scheduled in it.
Across the year
When delays peak on this route
Twelve months, one bar each, drawn from the same 1,266 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.
July is the worst month at 81.7% on time, 11 points below January, the best at 92.5%. 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. July was the busiest month here, with 129 flights.
Across the week, Saturday is the strongest day at 97.5% on time and Sunday the weakest at 83.6%. 14 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 8,604 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 50%Late-arriving aircraft
- 35%National Airspace System
- 12%Carrier
- 3%Extreme weather
50% 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 8,604 reported delay minutes here, that single category outweighs weather by 18 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 8,604 reported delay minutes.
35% 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 3,027 minutes out of 8,604, against a national NAS share of 21%.
Cancellations sit at 1.42% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 3.4% 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.
At 182 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 84.5% on time across 1,268 flights, 4 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 4 points of difference.
The sample behind these figures is 1,266 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.
Work out the risk of missing a connection in IAD after this flight
What to do with this
Booking this route
Put together: take the 5am–8am departure, avoid July if the dates are flexible, and if two carriers are within a few dollars of each other, Republic is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 24 points, which is the most any booking decision can do. 1,248 completed flights over 12 months sit behind that.
Common questions
PIT to IAD questions
How often is PIT 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 11.7% of the 1,266 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on PIT to IAD?
Republic Airways leads at 88.4% on time across 767 flights. United Airlines is at the other end on 88.1%, a gap of half a point. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on PIT to IAD?
The 5am–8am departure window is the strongest at 97.8% on time. The 2pm–5pm window is the weakest at 73.6%, 24 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 PIT to IAD?
July is the weakest month at 81.7% on time, compared with 92.5% in January. Across the year that is 11 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 PIT — the return legseparate record
- Pittsburgh International (PIT) delay statistics
- Washington Dulles International (IAD) delay statistics
- Republic Airways on PIT to IAD88.4%
- United Airlines on PIT to IAD88.1%
- PIT to ORD, a related route78.6%
- ATL to IAD, a related route76.5%
- PIT to LGA, a related route80.9%
- Republic Airways on-time record88.4%
- United Airlines on-time record88.1%
- 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. PIT to IAD and IAD to PIT 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.