San Juan (SJU) to Washington (IAD): On-Time Performance
Data through July 2026
San Juan (SJU) to Washington (IAD) effectively runs on two schedules. In April 2025, 95% of arrivals were on time; in August 2025 that fell to 72% — a 23-point seasonal swing. Across the full period the route averages 86% on-time against a national 78%. Morning departures also hold up better than evening ones (94% vs 84%), which matters most in the rough months.
- On-time
- 86%
- arrived <15 min late
- Avg delay
- 10 min
- completed flights
- Cancelled
- 0.6%
- Flights/day
- 1.9
- last 12 months
- Duration
- 4h 1m
- scheduled
- Distance
- 1,572 mi
Best airline from SJU to IAD
2 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 87% | 8 min | 0.5% | 1,155 |
| Frontier Airlines | 67% | 30 min | 1.0% | 104 |
Monthly on-time trend
Best time to fly from SJU to IAD
Aim for departures around 8 a.m. (94% on-time); avoid 4 p.m. departures (77%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 87% | 11 min |
| Tuesdaybest | 89% | 6 min |
| Wednesday | 88% | 8 min |
| Thursday | 82% | 13 min |
| Friday | 88% | 7 min |
| Saturday | 81% | 11 min |
| Sunday | 85% | 10 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft43%
- Airline operations30%
- National airspace system27%
- Weather1%
Frequently asked questions
- How often are flights from SJU to IAD delayed?
- 15% of SJU–IAD flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 10 minutes.
- Which airline is most reliable from SJU to IAD?
- United Airlines has the best on-time record on this route at 87%, based on 1,155 flights. 2 airlines flew SJU–IAD frequently enough to compare in this period.
- What is the best time of day to fly from SJU to IAD?
- Departures around 8 a.m. have the best record (94% on-time), while departures around 4 p.m. have the worst (77%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SJU to IAD?
- The scheduled SJU–IAD flight time averages 4h 1m over 1,572 miles. Actual arrival times vary — flights on this route land 15+ minutes late 15% of the time.
- How often are SJU to IAD flights cancelled?
- 0.6% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from SJU to IAD?
- August 2025 was the roughest month in this dataset, with only 72% of arrivals on time. The best was April 2025 at 95%. If your dates are flexible, that 23-point gap is worth planning around.
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Based on 1,259 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.