57% of flights from St. Louis to San Francisco arrived on time over the past 12 months. That is worse than the typical U.S. route. The 5 p.m. departures ran on time 74% of the time; the 7 p.m. ones 28%. Most reliable airline: United Airlines (58%). 20% 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 STL → SFO: when a flight was late, it was under 45 minutes late 41% of the time. About 1 in 5 flights landed an hour or more late, and 1 in 63 three hours or more; 0.7% were cancelled outright.
- On time or early57%
- 15–30 min late11%
- 30–60 min late12%
- 1–2 hours late15%
- 2–3 hours late2.7%
- 3+ hours late1.6%
- Diverted0.0%
- Cancelled0.7%
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 | 58% | 1.2% | +6 min | 18.7% | +81 min | SkyWest 57%, United Airlines 43% |
| Southwest Airlines | 342 | 56% | 0.0% | +7 min | 19.9% | +63 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 STL). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | United Airlines | Southwest Airlines |
|---|---|---|
| 8 a.m. | — | 40% |
| 5 p.m. | 80% | — |
| 7 p.m. | 28% | — |
By month
Each calendar month pooled over 2023–2026. Best: January (83%). Worst: June (42%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 119 | 53% | 0.8% |
| Tuesday | 102 | 69% | 0.0% |
| Wednesday | 107 | 55% | 0.0% |
| Thursday | 110 | 53% | 0.0% |
| Friday | 116 | 57% | 0.9% |
| Saturday | 83 | — | — |
| Sunday | 117 | 55% | 0.9% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 4 · airline 1
Month by month
Not enough months with data to draw a trend.
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Apr 17, 2026 | 3 | 0% | 1 |
| Apr 30, 2026 | 3 | 0% | 0 |
| May 13, 2026 | 3 | 0% | 0 |
| Apr 10, 2026 | 3 | 0% | 0 |
| Apr 12, 2026 | 3 | 0% | 0 |
Questions
How often are flights from STL to SFO on time?
57% of 754 scheduled flights from St. Louis, MO to San Francisco, CA arrived within 15 minutes of schedule between September 2025 and August 2026. 0.7% were cancelled.
What is the best time of day to fly STL to SFO?
Flights scheduled to leave at 5 p.m. were the most reliable (74% on time). The 7 p.m. departures were the least (28%).
Which airline is most on time from STL to SFO?
United Airlines: 58% of its 412 flights on the route arrived on time. Southwest Airlines: 56%.
What month has the most delays from STL to SFO?
June (42% on time). The best month is January (83%), over 2023–2026.
Related
- SFO → STL (return)
- St. Louis Lambert (STL) delays by hour
- Flights into San Francisco (SFO)
- 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.