Carrier route record
OOSTL→SFO
SkyWest Airlines · St. Louis to San Francisco
- Flights
- 233
- Period
- July 2025 to June 2026
- Share of route
- 30%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with SkyWest Airlines.
SkyWest on STL to SFO draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 233 flights, with a median arrival 5 minutes late.
The national on-time rate over the same period is 77.6%, so SkyWest on STL to SFO runs 14 points behind the country as a whole. Across a thousand flights that is about 144 extra late arrivals.
Key figures
On time
63.2%
Arrivals under 15 minutes late, of 228 completed flights
Avg delay
96 min
Across delayed arrivals only, not all flights
Cancelled
2.15%
National rate is 1.81%
Whole route
63.0%
Every carrier on STL to SFO, 782 flights
These figures cover 233 flights between July 2025 and June 2026. Beyond the headline rate, 18.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
SkyWest against every carrier on STL to SFO
SkyWest flew 233 of the 782 flights on STL to SFO, about 30% of it. Its 63.2% on time is about level with the route as a whole at 63.0%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from United at 63.6% to Southwest at 62.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlinesthin sample | 207 | 63.6% | 68 min | 0.48% | D+ |
| SkyWest Airlines (this page)thin sample | 233 | 63.2% | 96 min | 2.15% | D |
| Southwest Airlinesthin sample | 342 | 62.5% | 58 min | 0.29% | D+ |
Departure window
When SkyWest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 22 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am54 flights73.6%
- 8am–11am56 flights51.9%
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm123 flights63.6%
- 8pm–5am—
Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 73.6% of the time, against 51.9% for the morning window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 123 flights scheduled in it.
Across the year
SkyWest on STL to SFO through the year
- Jul–Sep 20256 flights—
- Oct–Dec 202539 flights69.2%
- Jan–Mar 2026104 flights82.2%
- Apr–Jun 202684 flights36.6%
Scale runs 30% to 90%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 63.2% on time across 233 flights.
SkyWest on STL to SFO did not run the same all year. Its best quarter was Jan–Mar 2026 at 82.2% on time and its weakest Apr–Jun 2026 at 36.6%, a swing of 46 points on roughly 78 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Sunday is the strongest day at 65.8% on time and Monday the weakest at 57.9%. 8 points is a smaller lever than departure hour, but it is free.
Delay causes
Why SkyWest runs late on this route
One category carries most of the weight here. Carrier accounts for 45% of the 8,028 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.
- 45%Carrier
- 44%National Airspace System
- 10%Late-arriving aircraft
- 1%Extreme weather
- 0%Security
The largest share of delay minutes, 45%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 3,614 of the 8,028 delay minutes reported here. The split is drawn from 8,028 reported delay minutes.
44% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,522 minutes out of 8,028, against a national NAS share of 21%.
Cancellations sit at 2.15% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 18.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 1,735 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 77.6% on time across 235 flights, 14 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 14 points of difference.
One caution: this is a thin sample. 233 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking SkyWest on STL to SFO
Put together: treat all of this as provisional. 233 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 63.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 228 completed flights over 12 months sit behind that.
Related
Where to go next
- STL to SFO, every carrier
- SkyWest on SFO to STL, the return leg
- United Airlines on STL to SFO63.6%
- Southwest Airlines on STL to SFO62.5%
- SkyWest Airlines network-wide record
- St. Louis Lambert International (STL) delay statistics
- San Francisco International (SFO) delay statistics
- How often a connection fails at the major US hubs
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.