Best Time to Fly IAD to SAN: On-Time Stats by Hour & Airline
Washington Dulles International → San Diego International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 84.4% of Washington (IAD) to San Diego (SAN) flights arrived on time (1,402 scheduled flights). That is 6.8 points above the national average of 77.6%.
Among 2 airlines, United Airlines led with 87.8% on time and Alaska Airlines was last with 74.7%.
Over 24 months, Tuesday was the most reliable day (85% on time) and June the worst month (75%).
The cancellation rate was 0.6% (US average 1.8%).
IAD to SAN 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 | 87.8% | 61 min | 0.6% | 1,041 |
| Alaska Airlines | 74.7% | 46 min | 0.6% | 361 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAD to SAN
On-time arrival % by scheduled departure hour (local time), 2,857 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 8am–9am | 90.5% | 0.2% | 490 |
| 9am–10am | 96.1% | 1.0% | 209 |
| 12pm–1pm | 88.2% | 0.6% | 503 |
| 1pm–2pm | 79.0% | 0.4% | 225 |
| 4pm–5pm | 82.9% | 0.0% | 70 |
| 5pm–6pm | 75.0% | 0.4% | 735 |
| 6pm–7pm | 71.0% | 0.4% | 545 |
| 7pm–8pm | 65.3% | 0.0% | 73 |
| 8pm–9pm | Limited data | 7 | |
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 SAN
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) | 78.8% | -3.6 pts | 0.0% | 52 |
| Christmas & New Year (Dec 20 - Jan 3) | 74.0% | -8.5 pts | 0.0% | 120 |
| Summer peak (Jun 15 - Aug 15) | 76.5% | -6.0 pts | 0.4% | 494 |
| All other days | 82.5% | — | 0.5% | 2,191 |
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).