Best Time to Fly IAD to PHX: On-Time Stats by Hour & Airline
Washington Dulles International → Phoenix Sky Harbor International
Data through July 2026 · Last updated October 18, 2026
1,036 flights were scheduled from Washington (IAD) to Phoenix (PHX) in the last 12 months, and 81.8% of those that flew arrived on time, 4.1 points above the US average of 77.6%.
Among 2 airlines, United Airlines led with 86.2% on time and Southwest Airlines was last with 71.2%.
Over 24 months, Tuesday was the most reliable day (85% on time) and July the worst month (64%).
The cancellation rate was 0.8% (US average 1.8%).
IAD to PHX on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| United Airlines | 86.2% | 68 min | 0.8% | 730 |
| Southwest Airlines | 71.2% | 45 min | 0.7% | 306 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAD to PHX
On-time arrival % by scheduled departure hour (local time), 2,278 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | Limited data | 4 | |
| 7am–8am | Limited data | 5 | |
| 8am–9am | 93.7% | 0.6% | 481 |
| 9am–10am | Limited data | 15 | |
| 12pm–1pm | 88.2% | 1.1% | 369 |
| 1pm–2pm | 80.7% | 0.0% | 31 |
| 2pm–3pm | Limited data | 15 | |
| 3pm–4pm | 83.6% | 0.0% | 128 |
| 4pm–5pm | 74.8% | 0.5% | 218 |
| 5pm–6pm | 75.9% | 0.7% | 895 |
| 6pm–7pm | 62.5% | 1.4% | 73 |
| 7pm–8pm | 75.0% | 0.0% | 44 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on IAD to PHX
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 84.3% | +0.9 pts | 0.0% | 51 |
| Christmas & New Year (Dec 20 - Jan 3) | 82.5% | -1.0 pts | 0.0% | 120 |
| Summer peak (Jun 15 - Aug 15) | 70.7% | -12.8 pts | 1.1% | 277 |
| All other days | 83.5% | — | 0.7% | 1,830 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).