St. Louis (STL) to San Francisco (SFO): On-Time Performance
Data through May 2026
The calendar drives reliability on STL–SFO. October 2024 flights landed on schedule 89% of the time, but May 2026 dropped to 32% — a gap of 56 points. Across the full period the route averages 71% on-time against a national 78%.
- On-time
- 71%
- arrived <15 min late
- Avg delay
- 21 min
- completed flights
- Cancelled
- 0.6%
- Flights/day
- 2.2
- last 12 months
- Duration
- 4h 28m
- scheduled
- Distance
- 1,735 mi
Best airline from STL to SFO
3 airlines flew this route regularly between 2024-06 and 2026-05.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 79% | 19 min | 0.5% | 560 |
| Southwest Airlines | 67% | 19 min | 0.1% | 701 |
| SkyWest Airlines | 66% | 32 min | 1.8% | 273 |
Monthly on-time trend
Best time to fly from STL to SFO
Aim for departures around 7 a.m. (91% on-time); avoid 7 p.m. departures (48%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 70% | 21 min |
| Tuesdaybest | 77% | 20 min |
| Wednesday | 73% | 17 min |
| Thursday | 70% | 22 min |
| Friday | 72% | 23 min |
| Saturday | 75% | 19 min |
| Sunday | 65% | 27 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft24%
- Airline operations36%
- National airspace system38%
- Weather2%
Frequently asked questions
- How often are flights from STL to SFO delayed?
- 29% of STL–SFO flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-06 and 2026-05. The average arrival delay across completed flights was 21 minutes.
- Which airline is most reliable from STL to SFO?
- United Airlines has the best on-time record on this route at 79%, based on 560 flights. 3 airlines flew STL–SFO frequently enough to compare in this period.
- What is the best time of day to fly from STL to SFO?
- Departures around 7 a.m. have the best record (91% on-time), while departures around 7 p.m. have the worst (48%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from STL to SFO?
- The scheduled STL–SFO flight time averages 4h 28m over 1,735 miles. Actual arrival times vary — flights on this route land 15+ minutes late 29% of the time.
- How often are STL to SFO flights cancelled?
- 0.6% of scheduled flights on this route were cancelled between 2024-06 and 2026-05, at or below the national rate of 1.6%.
- What is the worst month to fly from STL to SFO?
- May 2026 was the roughest month in this dataset, with only 32% of arrivals on time. The best was October 2024 at 89%. If your dates are flexible, that 56-point gap is worth planning around.
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Based on 1,534 flights, 2024-06–2026-05. Source: US DOT Bureau of Transportation Statistics. Updated 2026-07-01.