STL to SFO flight delays
St. Louis, MO (STL) San Francisco, CA (SFO) · 1,735 miles
782 flights · January 2025 – August 2026 · US Bureau of Transportation Statistics
62.97%
Arrived on time
Within 15 minutes of schedule
0.9%
Cancelled
Share of scheduled flights
72 min
When late, late by
Average across delayed arrivals
28 min
Delay per flight
Averaged over every flight flown
What the record says about this route
The season swings this route hard. In January it ran 69.8 points more punctual than in June — 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.
The route has been getting worse. The later months run 14.2 points less punctual than the earlier ones. A drift of that size is rarely weather; it is more often an airline adding frequencies faster than the airports can absorb them.
This is a late route. Flights from St. Louis to San Francisco 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. STL as a whole runs 12.5 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 STL to SFO. Southwest Airlines was late most often. Flights ran closest to schedule in January and worst in June.
Every airline on STL to SFO
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 | 62.46% | 0.29% | 58 min | F |
| SkyWest Airlines | 233 | 63.16% | 2.15% | 96 min | F |
| United Airlines | 207 | 63.59% | 0.48% | 68 min | F |
Month by month
Share of flights that arrived within 15 minutes of schedule, by month flown.
The return leg
SFO to STL San Francisco back to St. Louis 65.76% on time FOther routes from St. Louis
Common questions
Are flights from St. Louis to San Francisco usually delayed?
62.97% of flights on the STL to SFO route arrived within 15 minutes of schedule, so roughly 4 in every ten arrived late. That is worse than the average route in this record.
Which airline is most on time from St. Louis to San Francisco?
United Airlines, at 63.59% on time across 207 flights. The least punctual on the route was Southwest Airlines at 62.46%.
How often are STL to SFO 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 St. Louis to San Francisco?
January, when 88.1% of flights arrived on time. The worst was June at 18.3%.
When STL to SFO flights are late, how late are they?
About 72 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 SFO 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 →