60% of flights from San Francisco to St. Louis arrived on time over the past 12 months. That is worse than the typical U.S. route. The 10 a.m. departures ran on time 64% of the time; the noon ones 50%. Most reliable airline: United Airlines (76%). 16% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for SFO → STL: when a flight was late, it was under 45 minutes late 48% of the time. About 1 in 7 flights landed an hour or more late, and 1 in 75 three hours or more; 0.9% were cancelled outright.
- On time or early60%
- 15–30 min late11%
- 30–60 min late13%
- 1–2 hours late11%
- 2–3 hours late2.3%
- 3+ hours late1.3%
- Diverted0.7%
- Cancelled0.9%
Share of all 754 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| United Airlines | 412 | 76% | 1.5% | −8 min | 7.3% | +72 min | SkyWest 57%, United Airlines 43% |
| Southwest Airlines | 342 | 40% | 0.3% | +25 min | 23.4% | +61 min | Southwest Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at SFO). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | United Airlines |
|---|---|
| 10 a.m. | 83% |
| noon | 69% |
By month
Each calendar month pooled over 2023–2026. Best: January (80%). Worst: July (60%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 114 | 53% | 0.9% |
| Tuesday | 101 | 65% | 0.0% |
| Wednesday | 108 | 56% | 0.0% |
| Thursday | 115 | 57% | 0.9% |
| Friday | 111 | 59% | 0.0% |
| Saturday | 88 | — | — |
| Sunday | 117 | 63% | 0.0% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 4 · airline 2 · air traffic/airport 1
Month by month
Not enough months with data to draw a trend.
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| May 6, 2026 | 3 | 0% | 0 |
| Feb 5, 2026 | 3 | 0% | 0 |
| Apr 27, 2026 | 3 | 0% | 1 |
| Apr 20, 2026 | 3 | 0% | 0 |
| Apr 30, 2026 | 3 | 33% | 0 |
Questions
How often are flights from SFO to STL on time?
60% of 754 scheduled flights from San Francisco, CA to St. Louis, MO arrived within 15 minutes of schedule between September 2025 and August 2026. 0.9% were cancelled.
What is the best time of day to fly SFO to STL?
Flights scheduled to leave at 10 a.m. were the most reliable (64% on time). The noon departures were the least (50%).
Which airline is most on time from SFO to STL?
United Airlines: 76% of its 412 flights on the route arrived on time. Southwest Airlines: 40%.
What month has the most delays from SFO to STL?
July (60% on time). The best month is January (80%), over 2023–2026.
Related
- STL → SFO (return)
- San Francisco (SFO) delays by hour
- Flights into St. Louis Lambert (STL)
- United Airlines on-time record
- Southwest Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.