IAD to SJU flight delays & on-time performance
Nonstop flights from Washington Dulles International Airport to Luis Munoz Marin International Airport · 1,572 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at IAD or SJU right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Washington (IAD) to San Juan (SJU) arrived on time 76% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 0.6% were cancelled, and 6% arrived an hour or more late.
- United Airlines was the most punctual airline here (79% on time); Frontier Airlines was the least (51%).
- Departures scheduled around 8am did best (84% on time); around 8pm did worst (43%).
- Wednesday was the most reliable day to fly (90% on time) and Sunday the least (68%).
- The largest source of delay minutes was air traffic control & airport congestion (44%).
Which airline is most on time from IAD to SJU?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| United Airlines | 79% | 0.5% | 12 min | 4.9% | 632 |
| Frontier Airlines | 51% | 1.3% | 83 min | 18.9% | 75 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 8am84%347 flights
- 5pm72%285 flights
- 7pm57%14 flights
- 8pm43%31 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday74%0.0% cancelled
- Tuesday73%0.0% cancelled
- Wednesday90%0.0% cancelled
- Thursday78%0.0% cancelled
- Friday78%0.0% cancelled
- Saturday72%1.8% cancelled
- Sunday68%1.8% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Air traffic control & airport congestion44%
- Late-arriving aircraft35%
- Airline (crew, maintenance, cleaning, fueling)16%
- Extreme weather5%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather75%
- Air traffic control & airport congestion25%
- Airline (crew, maintenance, cleaning, fueling)0%
- Security0%
IAD to SJU: common questions
- How often are IAD to SJU flights on time?
- 76% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Washington to San Juan cancelled?
- 0.6% of scheduled flights were cancelled (4 of 707).
- How long are typical delays?
- Across all flights the average arrival delay was 20 min (early arrivals count as zero). Flights that were late arrived 77 min behind schedule on average, and 6.4% of flights were an hour or more late.
- How long is taxi time at IAD?
- Flights on this route spent 25 min taxiing from the gate to takeoff on average.
Related routes
Return trip: SJU to IAD — 87% on time
More flights from Washington
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: IAD → SJU, nonstop flights by US airlines that report to the DOT. How we calculate this.