STL to SJU flight delays & on-time performance
Nonstop flights from St. Louis Lambert International Airport to Luis Munoz Marin International Airport · 2,024 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at STL or SJU right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from St. Louis (STL) to San Juan (SJU) arrived on time 47% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 3.2% were cancelled, and 3% arrived an hour or more late.
- Southwest Airlines is the only airline reporting nonstop flights on this route.
- The largest source of delay minutes was air traffic control & airport congestion (45%).
Which airline is most on time from STL 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 |
|---|---|---|---|---|---|
| Southwest Airlines | 47% | 3.2% | 20 min | 3.3% | 31 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
Not enough departures across different hours to compare.
Best day of the week
On-time arrival rate by day of departure.
- Saturday47%3.2% 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 congestion45%
- Airline (crew, maintenance, cleaning, fueling)35%
- Late-arriving aircraft13%
- Extreme weather6%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Air traffic control & airport congestion100%
- Airline (crew, maintenance, cleaning, fueling)0%
- Extreme weather0%
- Security0%
STL to SJU: common questions
- How often are STL to SJU flights on time?
- 47% 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 St. Louis to San Juan cancelled?
- 3.2% of scheduled flights were cancelled (1 of 31).
- 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 33 min behind schedule on average, and 3.3% of flights were an hour or more late.
- How long is taxi time at STL?
- Flights on this route spent 14 min taxiing from the gate to takeoff on average.
Related routes
Return trip: SJU to STL — 77% on time
More flights from St. Louis
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: STL → SJU, nonstop flights by US airlines that report to the DOT. How we calculate this.