Route reliability record
PHX→IAD
Phoenix to Washington
- Flights
- 1,098
- Period
- July 2025 to June 2026
- Distance
- 1,956 mi
- Carriers
- 2
This route earns a B+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 1,098 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 Saturday. Flights in that window arrived on time 92.6% of the time and Saturday flights 87.6%, against 84.7% for the route overall.
Set against the rest of the country, this route's record is 7 points better than the US average of 77.6%. That gap is worth roughly 71 fewer late arrivals for every thousand flights.
Key figures
On time
84.7%
Arrivals under 15 minutes late, of 1,081 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.64%
National rate is 1.81%
Best carrier
United
89.7% on time across 761 flights
These figures cover 1,098 flights between July 2025 and June 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.
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 | 761 | 89.7% | 73 min | 0.79% | A+ |
| Southwest Airlinesthin sample | 337 | 73.5% | 40 min | 0.30% | 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.
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 | 89.0% | 89.7% | 0.79% | 5am–8am, Thu | UA 1873 09:00 |
| 2. PHX → DCAPhoenix to Washington | American Airlines | 82.7% | 83.9% | 1.47% | 8pm–5am, Sat | — |
| 3. PHX → BWIPhoenix to Baltimore | Southwest Airlines | 79.5% | 80.3% | 1.01% | 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 11 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–8am82 flights92.6%
- 8am–11am504 flights81.2%
- 11am–2pm243 flights82.4%
- 2pm–5pm130 flights91.5%
- 5pm–8pm—
- 8pm–5am139 flights91.0%
Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.6% of the time, against 81.2% for the morning window. That is 11 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 504 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 26 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 72.4% on time, 26 points below January, the best at 97.9%. 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. March was the busiest month here, with 117 flights.
Across the week, Saturday is the strongest day at 87.6% on time and Sunday the weakest at 77.4%. 10 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. Carrier accounts for 48% of the 9,183 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.
- 48%Carrier
- 26%Late-arriving aircraft
- 21%National Airspace System
- 3%Security
- 1%Extreme weather
The largest share of delay minutes, 48%, 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 4,452 of the 9,183 delay minutes reported here. The split is drawn from 9,183 reported delay minutes.
Cancellations are rare at 0.64%, 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 3.6% 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 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 79.9% on time across 1,097 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.
The sample behind these figures is 1,098 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: the calendar is the biggest lever here, not the carrier or the hour. January runs 97.9% on time and July 72.4%, a swing of 26 points. If the dates move at all, move them out of July before you think about anything else. 1,081 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 15.3% of the 1,098 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
How reliable is PHX to IAD compared with the rest of the country?
84.7% of flights arrive on time here against a national 77.6%, a difference of 7 points in its favour. That is worth a B+ 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 8am–11am window is the weakest at 81.2%, 11 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 PHX to IAD?
July is the weakest month at 72.4% on time, compared with 97.9% in January. Across the year that is 26 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 IAD89.7%
- Southwest Airlines on PHX to IAD73.5%
- PHX to DEN, a related route77.2%
- ATL to IAD, a related route76.5%
- PHX to LAX, a related route82.8%
- United Airlines on-time record89.7%
- Southwest Airlines on-time record73.5%
- The best time of day to fly, according to 7.04 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.