STL to SJU flight delays
St. Louis, MO (STL) San Juan, PR (SJU) · 2,024 miles
31 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
This route flew fewer than 50 times in the period, which is too few for an on-time rate to mean anything. The figures below are shown as recorded, but the route is not graded.
46.67%
Arrived on time
Within 15 minutes of schedule
3.23%
Cancelled
Share of scheduled flights
34 min
When late, late by
Average across delayed arrivals
20 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Flights from St. Louis to San Juan arrive late more often than they arrive on time. At this rate lateness is the normal outcome, not the exception, and the schedule is better read as an aspiration than a plan.
The two directions do not behave alike. SJU to STL arrives on time 30 points more often than the outbound. Delay accumulates through the flying day, so whichever direction is scheduled later tends to carry the worse record — which is an argument for booking the morning departure if the choice exists.
Cancellation, not delay, is the risk worth pricing here: 3.23% of scheduled flights never operated. A late flight still gets you there. A cancelled one leaves you rebooking, and on a route with few daily departures that can mean losing a day.
Lateness here is frequent but mild: flights slip past the fifteen-minute line often, yet the average delay is only about 34 minutes. That is an annoyance rather than a broken plan, and it is a very different route from one with the same on-time rate and hour-long delays.
Every airline on STL to SJU
Ranked by how many flights each one operated. A carrier with fewer than 100 flights in the period is listed but not graded.
| Airline | Flights | On time | Cancelled | Avg delay | Grade |
|---|---|---|---|---|---|
| Southwest Airlines | 31 | 46.67% | 3.23% | 34 min | — |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
SJU to STL San Juan back to St. Louis 76.67% on time —Other routes from St. Louis
Common questions
Are flights from St. Louis to San Juan usually delayed?
46.67% of flights on the STL to SJU route arrived within 15 minutes of schedule, so roughly 5 in every ten arrived late. That is worse than the average route in this record.
How often are STL to SJU flights cancelled?
3.23% of scheduled flights did not operate — about 32 in every thousand. That is high enough that cancellation, not delay, is the risk worth planning around.
When STL to SJU flights are late, how late are they?
About 34 minutes on average across the flights that arrived more than 15 minutes behind schedule.
What these figures do and do not tell you
Everything on this page is counted from the flights that actually operated on STL to SJU during January 2025 – August 2026, as reported by the airlines to the US Bureau of Transportation Statistics. "On time" is the federal definition: arriving at the gate within 15 minutes of the scheduled time.
A route's record is a description of the past, not a forecast. Weather, air traffic control and the aircraft's earlier flights that day drive most delays, and none of them are predictable from a historical rate. What the record does tell you is whether this route runs late more often than others, and which carrier on it has the better history — which is the part you can actually act on when you book.
Cancellations are counted separately from delays because they are a different problem for a traveller: a late flight still gets you there. How the grade is calculated →