Carrier route record
UAIAD→PIT
United Airlines · Washington to Pittsburgh
- Flights
- 517
- Period
- September 2025 to August 2026
- Share of route
- 43%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with United Airlines.
United on IAD to PIT 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 10 points better than the national rate of 77.3%. When something does go wrong the average delay runs a little over an hour. That rests on 517 flights, with a median arrival 7 minutes early.
Set against the rest of the country, United's IAD to PIT record is 10 points better than the US average of 77.3%. That gap is worth roughly 102 fewer late arrivals for every thousand flights.
Key figures
On time
87.5%
Arrivals under 15 minutes late, of 512 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
0.77%
National rate is 1.89%
Whole route
84.3%
Every carrier on IAD to PIT, 1,213 flights
These figures cover 517 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
United against every carrier on IAD to PIT
United flew 517 of the 1,213 flights on IAD to PIT, about 43% of it. Its 87.5% on time is 3 points better than the route as a whole, which runs 84.3%. Ranked by on-time rate it is first of two carriers on the route, where the range runs from United at 87.5% to Republic at 81.9%.
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 (this page) | 517 | 87.5% | 79 min | 0.77% | A+ |
| Republic Airways | 696 | 81.9% | 74 min | 2.44% | B |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 13 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am203 flights92.5%
- 11am–2pm154 flights89.5%
- 2pm–5pm—
- 5pm–8pm160 flights79.2%
- 8pm–5am—
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 92.5% of the time, against 79.2% for the evening window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 203 flights scheduled in it.
Across the year
United on IAD to PIT through the year
April is the best month on the calendar at 94.5% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. February was the busiest month here, with 62 flights.
Across the week, Wednesday is the strongest day at 92.9% on time and Sunday the weakest at 83.6%, a spread of 9 points.
Arrival by arrival
How late United on IAD to PIT runs when it is late
The 64 late arrivals split 23 under half an hour, 17 between 30 and 60 minutes, and 24 an hour or more.
- 15+ min early101 flights19.7%
- Within 15 min347 flights67.8%
- 15–29 min late23 flights4.5%
- 30–59 min late17 flights3.3%
- 1–2 hours late10 flights2.0%
- 2+ hours late14 flights2.7%
Scale runs 0% to 100%.
Share of 512 completed flights by arrival against schedule.
10 of 49 late departures made up the time and arrived on time, 20% of them. 25 flights left on time and still arrived late.
The worst days
Worst days for United on IAD to PIT
The latest arrival of the period was on 13 March 2026, 6 hours 11 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in March 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 13 March 2026 | 6 hours 11 minutes | Carrier |
| 10 June 2026 | 5 hours 6 minutes | Extreme weather |
| 1 March 2026 | 4 hours 40 minutes | Late-arriving aircraft |
| 26 March 2026 | 4 hours 37 minutes | Late-arriving aircraft |
| 17 July 2026 | 4 hours 8 minutes | Late-arriving aircraft |
Delay causes
Why United runs late on this route
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 5,061 reported delay minutes.
- 37%Late-arriving aircraft
- 28%Carrier
- 26%National Airspace System
- 9%Extreme weather
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 5,061 reported delay minutes here, that single category outweighs weather by 4 to one. The split is drawn from 5,061 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 92.5% on time here.
Cancellations are rare at 0.77%, 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
Badly late arrivals are rare here: only 4.7% 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.
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 8am–11am window matters as much as it does.
The return leg runs 86.0% on time across 517 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 517 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.
What to do with this
Booking United on IAD to PIT
Put together: treat all of this as provisional. 517 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 87.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 512 completed flights over 12 months sit behind that.
Related
Where to go next
- IAD to PIT, every carrier
- United on PIT to IAD, the return leg
- Republic Airways on IAD to PIT81.9%
- United Airlines network-wide record
- Washington Dulles International (IAD) delay statistics
- Pittsburgh International (PIT) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.