San Francisco (SFO) to St. Louis (STL): On-Time Performance
Data through July 2026
When you fly SFO to STL matters as much as anything else about the booking: the route swung from 91% on-time in January 2026 to just 43% in July 2026. Across the full period the route averages 69% on-time against a national 78%.
- On-time
- 69%
- arrived <15 min late
- Avg delay
- 20 min
- completed flights
- Cancelled
- 0.7%
- Flights/day
- 2.1
- last 12 months
- Duration
- 3h 57m
- scheduled
- Distance
- 1,735 mi
Best airline from SFO to STL
3 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 78% | 13 min | 0.5% | 618 |
| SkyWest Airlines | 78% | 18 min | 2.2% | 275 |
| Southwest Airlines | 57% | 26 min | 0.4% | 733 |
Monthly on-time trend
Best time to fly from SFO to STL
Aim for departures around 6 a.m. (97% on-time); avoid 1 p.m. departures (51%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 62% | 27 min |
| Tuesday | 73% | 16 min |
| Wednesday | 67% | 16 min |
| Thursday | 65% | 23 min |
| Friday | 65% | 19 min |
| Saturdaybest | 80% | 16 min |
| Sunday | 71% | 19 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft58%
- Airline operations28%
- National airspace system14%
- Weather1%
Frequently asked questions
- How often are flights from SFO to STL delayed?
- 32% of SFO–STL flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 20 minutes.
- Which airline is most reliable from SFO to STL?
- United Airlines has the best on-time record on this route at 78%, based on 618 flights. 3 airlines flew SFO–STL frequently enough to compare in this period.
- What is the best time of day to fly from SFO to STL?
- Departures around 6 a.m. have the best record (97% on-time), while departures around 1 p.m. have the worst (51%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from SFO to STL?
- The scheduled SFO–STL flight time averages 3h 57m over 1,735 miles. Actual arrival times vary — flights on this route land 15+ minutes late 32% of the time.
- How often are SFO to STL flights cancelled?
- 0.7% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from SFO to STL?
- July 2026 was the roughest month in this dataset, with only 43% of arrivals on time. The best was January 2026 at 91%. If your dates are flexible, that 48-point gap is worth planning around.
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Based on 1,626 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.