Route reliability record
PHX→IAD
Phoenix to Washington
- Flights
- 979
- Period
- September 2025 to August 2026
- Distance
- 1,956 mi
- Carriers
- 2
This route earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.3%. When something does go wrong the average delay runs about 45 minutes. That rests on 979 PHX to IAD flights, with a median arrival 8 minutes early.
Best time to fly PHX to IAD: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 92.6% of the time and Wednesday flights 89.9%, against 86.1% for the route overall.
Set against the rest of the country, this route's record is 9 points better than the US average of 77.3%. That gap is worth roughly 88 fewer late arrivals for every thousand flights.
Key figures
On time
86.1%
Arrivals under 15 minutes late, of 967 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
0.61%
National rate is 1.89%
Best carrier
United
90.8% on time across 704 flights
These figures cover 979 flights between September 2025 and August 2026. The median arrival is 8 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 PHX 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 | 704 | 90.8% | 57 min | 0.71% | A+ |
| Southwest Airlinesthin sample | 275 | 74.3% | 35 min | 0.36% | C+ |
Flight by flight
Flights on PHX 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 Phoenix 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 3 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. PHX → IADPhoenix to Washington | United Airlines | 90.2% | 90.8% | 0.71% | 5am–8am, Wed | UA 1873 08:50 |
| 2. PHX → DCAPhoenix to Washington | American Airlines | 80.8% | 82.0% | 1.47% | 8pm–5am, Sat | — |
| 3. PHX → BWIPhoenix to Baltimore | Southwest Airlines | 77.8% | 78.5% | 0.90% | 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 is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 979 flights.
- 5am–8am82 flights92.6%
- 8am–11am456 flights83.7%
- 11am–2pm222 flights83.5%
- 2pm–5pm129 flights91.4%
- 5pm–8pm—
- 8pm–5am90 flights92.0%
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 83.5% on time against 92.6% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8am–11am window is the busiest, with 456 flights scheduled in it.
Explore
Filter PHX 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 PHX to IAD, the best departure window is 5am–8am at 92.6% on time and the worst is 11am–2pm at 83.5%, a real gap of 9.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.6%
- 8–11am83.7%
- 11am–2pm83.5%
- 2–5pm91.4%
- 5–8pm—
- 8pm–5am92.0%
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 18 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.
Delays peak in March, when the on-time rate falls to 79.6%. January is the strongest month at 97.9%. Moving a flexible trip across that boundary buys 18 points. March was the busiest month here, with 117 flights.
Across the week, Wednesday is the strongest day at 89.9% on time and Sunday the weakest at 80.6%, a spread of 9 points.
Delay causes
Why this route gets delayed
Carrier accounts for 46% of the 6,056 delay minutes carriers reported here, and the remaining four split what is left.
- 46%Carrier
- 29%Late-arriving aircraft
- 24%National Airspace System
- 2%Extreme weather
The largest share of delay minutes, 46%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 2,761 of the 6,056 delay minutes reported here. The split is drawn from 6,056 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 92.6% on time here.
Cancellations are rare at 0.61%, 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 2.6% 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 1,956 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 81.2% on time across 979 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. 979 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. 979 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 86.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 967 completed flights over 12 months sit behind that.
Common questions
PHX to IAD questions
How often is PHX to IAD delayed?
About one flight in seven arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.9% of the 979 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 45 minutes on average.
How reliable is PHX to IAD compared with the rest of the country?
86.1% of flights arrive on time here against a national 77.3%, a difference of 9 points in its favour. That is worth a A+ on this site's grading scale.
What time of day has the fewest delays on PHX to IAD?
The 5am–8am departure window is the strongest at 92.6% on time. The 11am–2pm window is the weakest at 83.5%, 9 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 March delays on PHX to IAD?
March is the weakest month at 79.6% on time, compared with 97.9% in January. Across the year that is 18 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 PHX — the return legseparate record
- Phoenix Sky Harbor International (PHX) delay statistics
- Washington Dulles International (IAD) delay statistics
- United Airlines on PHX to IAD90.8%
- Southwest Airlines on PHX to IAD74.3%
- PHX to DEN, a related route76.7%
- ATL to IAD, a related route76.4%
- PHX to LAX, a related route82.1%
- United Airlines on-time record90.8%
- Southwest Airlines on-time record74.3%
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Direction matters. PHX to IAD and IAD to PHX 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.