SFO to STL flight delays
San Francisco, CA (SFO) St. Louis, MO (STL) · 1,735 miles
781 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
65.76%
Arrived on time
Within 15 minutes of schedule
0.9%
Cancelled
Share of scheduled flights
63 min
When late, late by
Average across delayed arrivals
23 min
Delay per flight
Averaged over every flight flown
What the record says about this route
Which airline you fly changes the odds here. United Airlines arrived on time 31.7 points more often than Southwest Airlines over the same period on the same route — same airports, same weather, same air traffic control. A gap that survives all of that is about how the two airlines are run.
The season swings this route hard. In January it ran 44.4 points more punctual than in May — a difference bigger than the one between the best and worst airlines on most routes. If the date is flexible, it is worth more than the carrier.
This is a late route. Flights from San Francisco to St. Louis miss their scheduled arrival often enough that a tight connection at the far end is a connection at risk.
This route does worse than its own airport. SFO as a whole runs 11.3 points more punctual than these flights, which points at something specific to the route — the time of day it is scheduled, or the aircraft that feed it — rather than the airport.
Which airline should you fly on this route?
Over January 2025 – August 2026, United Airlines arrived on time most often on SFO to STL. Southwest Airlines was late most often. Flights ran closest to schedule in January and worst in May.
Every airline on SFO to STL
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 | 342 | 48.97% | 0% | 59 min | F |
| SkyWest Airlines | 235 | 77.63% | 2.55% | 85 min | C |
| United Airlines | 204 | 80.69% | 0.49% | 52 min | B |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
STL to SFO St. Louis back to San Francisco 62.97% on time FOther routes from San Francisco
Common questions
Are flights from San Francisco to St. Louis usually delayed?
65.76% of flights on the SFO to STL route arrived within 15 minutes of schedule, so roughly 3 in every ten arrived late. That is worse than the average route in this record.
Which airline is most on time from San Francisco to St. Louis?
United Airlines, at 80.69% on time across 204 flights. The least punctual on the route was Southwest Airlines at 48.97%.
How often are SFO to STL flights cancelled?
0.9% of scheduled flights did not operate — about 9 in every thousand. That is in the normal range.
What is the best month to fly San Francisco to St. Louis?
January, when 90.9% of flights arrived on time. The worst was May at 46.5%.
When SFO to STL flights are late, how late are they?
About 63 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 SFO to STL 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 →