Best Time to Fly IAD to SAT: On-Time Stats by Hour & Airline
Washington Dulles International → San Antonio International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 86.0% of Washington (IAD) to San Antonio (SAT) flights arrived on time (641 scheduled flights). That is 8.4 points above the national average of 77.6%.
United Airlines was the only reporting airline with regular flights on this route.
October has been the best month (96% on time) and Saturday the weakest day of the week (76%).
0.6% of flights were cancelled, versus 1.8% nationally.
IAD to SAT 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 | 86.0% | 104 min | 0.6% | 641 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly IAD to SAT
On-time arrival % by scheduled departure hour (local time), 1,278 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 8am–9am | 93.3% | 0.9% | 559 |
| 5pm–6pm | 76.2% | 0.4% | 699 |
| 6pm–7pm | Limited data | 20 | |
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 SAT
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) | Limited data | 26 | ||
| Christmas & New Year (Dec 20 - Jan 3) | 84.9% | -1.0 pts | 0.0% | 53 |
| Summer peak (Jun 15 - Aug 15) | 74.5% | -11.4 pts | 0.9% | 226 |
| All other days | 85.9% | — | 0.6% | 973 |
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).