Best Time to Fly IAD to LAX: On-Time Stats by Hour & Airline
Washington Dulles International → Los Angeles International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 83.7% of Washington (IAD) to Los Angeles (LAX) flights arrived on time (2,472 scheduled flights). That is 6.1 points above the national average of 77.6%.
Among 2 airlines, United Airlines led with 84.4% on time and American Airlines was last with 75.7%.
Over 24 months, Friday was the most reliable day (85% on time) and July the worst month (71%).
The cancellation rate was 0.8% (US average 1.8%).
IAD to LAX 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 | 84.4% | 59 min | 0.8% | 2,338 |
| American Airlines | 75.7% | 54 min | 0.0% | 115 |
| Alaska Airlines | Limited data | 19 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAD to LAX
On-time arrival % by scheduled departure hour (local time), 5,077 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 90.6% | 0.2% | 439 |
| 7am–8am | 92.5% | 0.0% | 240 |
| 8am–9am | 88.0% | 1.3% | 616 |
| 9am–10am | 89.2% | 1.1% | 264 |
| 10am–11am | Limited data | 21 | |
| 12pm–1pm | 91.6% | 0.3% | 596 |
| 1pm–2pm | 88.1% | 0.0% | 134 |
| 2pm–3pm | 80.6% | 0.0% | 36 |
| 3pm–4pm | 79.6% | 0.3% | 325 |
| 4pm–5pm | 91.2% | 0.0% | 34 |
| 5pm–6pm | 69.1% | 1.0% | 728 |
| 6pm–7pm | 75.6% | 1.6% | 323 |
| 7pm–8pm | 80.7% | 0.3% | 334 |
| 8pm–9pm | 69.2% | 0.3% | 326 |
| 10pm–11pm | 83.9% | 0.5% | 661 |
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 LAX
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) | 86.3% | +0.9 pts | 1.0% | 96 |
| Christmas & New Year (Dec 20 - Jan 3) | 75.6% | -9.8 pts | 0.0% | 221 |
| Summer peak (Jun 15 - Aug 15) | 72.9% | -12.5 pts | 0.6% | 951 |
| All other days | 85.4% | — | 0.7% | 3,809 |
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).