Best Time to Fly SJU to IAD: On-Time Stats by Hour & Airline
Luis Munoz Marin International → Washington Dulles International
Data through July 2026 · Last updated October 18, 2026
706 flights were scheduled from San Juan (SJU) to Washington (IAD) in the last 12 months, and 87.2% of those that flew arrived on time, 9.5 points above the US average of 77.6%.
Among 2 airlines, United Airlines led with 90.0% on time and Frontier Airlines was last with 63.5%.
Over 24 months, Friday was the most reliable day (89% on time) and August the worst month (73%).
The cancellation rate was 0.7% (US average 1.8%).
SJU to IAD 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 | 90.0% | 55 min | 0.6% | 631 |
| Frontier Airlines | 63.5% | 100 min | 1.3% | 75 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SJU to IAD
On-time arrival % by scheduled departure hour (local time), 1,219 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | Limited data | 14 | |
| 7am–8am | 94.1% | 0.0% | 287 |
| 8am–9am | 94.3% | 0.9% | 213 |
| 12pm–1pm | Limited data | 2 | |
| 2pm–3pm | Limited data | 1 | |
| 3pm–4pm | Limited data | 14 | |
| 4pm–5pm | 77.7% | 0.5% | 436 |
| 5pm–6pm | 83.5% | 1.2% | 252 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SJU to IAD
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) | 77.9% | -8.9 pts | 4.2% | 71 |
| Summer peak (Jun 15 - Aug 15) | 84.0% | -2.8 pts | 0.0% | 220 |
| All other days | 86.8% | — | 0.4% | 902 |
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).