Best Time to Fly STL to SFO: On-Time Stats by Hour & Airline
St Louis Lambert International → San Francisco International
Data through July 2026 · Last updated October 18, 2026
Over the last 12 months, 60.3% of St. Louis (STL) to San Francisco (SFO) flights arrived on time (761 scheduled flights). That is 17.4 points below the national average of 77.6%.
SkyWest Airlines was the most punctual of the 3 airlines on the route at 63.2%, while Southwest Airlines trailed at 58.9%.
January has been the best month (85% on time) and Sunday the weakest day of the week (61%).
0.8% of flights were cancelled, versus 1.8% nationally.
STL to SFO on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| SkyWest Airlines | 63.2% | 96 min | 2.1% | 233 |
| United Airlines | 59.1% | 72 min | 0.0% | 186 |
| Southwest Airlines | 58.9% | 61 min | 0.3% | 342 |
80%+ good 70–79.9% fair <70% poor
Best time of day to fly STL to SFO
On-time arrival % by scheduled departure hour (local time), 1,595 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 65.1% | 0.8% | 127 |
| 7am–8am | 90.7% | 0.0% | 204 |
| 8am–9am | 48.6% | 2.2% | 183 |
| 9am–10am | 67.5% | 0.0% | 114 |
| 10am–11am | 85.1% | 0.0% | 67 |
| 11am–12pm | 79.7% | 0.0% | 59 |
| 12pm–1pm | 65.8% | 0.0% | 38 |
| 1pm–2pm | 71.7% | 0.0% | 92 |
| 2pm–3pm | 70.5% | 0.0% | 61 |
| 3pm–4pm | 71.7% | 0.0% | 53 |
| 4pm–5pm | 70.6% | 0.0% | 68 |
| 5pm–6pm | 75.2% | 1.1% | 281 |
| 6pm–7pm | 69.6% | 0.0% | 79 |
| 7pm–8pm | 38.5% | 0.6% | 157 |
| 8pm–9pm | Limited data | 5 | |
| 9pm–10pm | Limited data | 7 | |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on STL to SFO
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 57.6% | -16.2 pts | 0.0% | 33 |
| Christmas & New Year (Dec 20 - Jan 3) | 65.0% | -8.8 pts | 0.0% | 60 |
| Summer peak (Jun 15 - Aug 15) | 46.2% | -27.5 pts | 0.4% | 267 |
| All other days | 73.8% | — | 0.7% | 1,235 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).