Carrier route record
WNSAN→STS
Southwest Airlines · San Diego to Santa Rosa
- Flights
- 231
- Period
- September 2025 to August 2026
- Share of route
- 22%
- Carriers
- 2
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on SAN to STS sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 231 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.3%, so Southwest on SAN to STS runs 9 points behind the country as a whole. Across a thousand flights that is about 86 extra late arrivals.
Key figures
On time
68.7%
Arrivals under 15 minutes late, of 227 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
1.30%
National rate is 1.89%
Whole route
77.5%
Every carrier on SAN to STS, 1,064 flights
These figures cover 231 flights between September 2025 and August 2026. Beyond the headline rate, 8.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
Southwest against every carrier on SAN to STS
Southwest flew 231 of the 1,064 flights on SAN to STS, about 22% of it. Its 68.7% on time is 9 points worse than the route as a whole, which runs 77.5%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 80.1% to Southwest at 68.7%.
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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 833 | 80.1% | 51 min | 4.08% | B− |
| Southwest Airlines (this page)thin sample | 231 | 68.7% | 47 min | 1.30% | C |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 39 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am84 flights91.7%
- 11am–2pm—
- 2pm–5pm1 flights—
- 5pm–8pm20 flights—
- 8pm–5am126 flights52.5%
Scale runs 45% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 52.5% on time, against 91.7% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8pm–5am window is the busiest, with 126 flights scheduled in it.
Across the year
Southwest on SAN to STS through the year
- Apr–Jun 2026133 flights69.7%
- Jul–Sep 202698 flights67.4%
Scale runs 60% to 75%.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 68.7% on time across 231 flights.
Split by quarter, Southwest on SAN to STS logged 133 flights in Apr–Jun 2026 and 98 flights in Jul–Sep 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 68.7% annual figure is the one to use.
Arrival by arrival
How late Southwest on SAN to STS runs when it is late
The 71 late arrivals split 28 under half an hour, 23 between 30 and 60 minutes, and 20 an hour or more.
- 15+ min early51 flights22.5%
- Within 15 min105 flights46.3%
- 15–29 min late28 flights12.3%
- 30–59 min late23 flights10.1%
- 1–2 hours late19 flights8.4%
- 2+ hours late1 flights0.4%
Scale runs 0% to 100%.
Share of 227 completed flights by arrival against schedule.
21 of 89 late departures made up the time and arrived on time, 24% of them. Only 3 left on time and still arrived late.
The worst days
Worst days for Southwest on SAN to STS
The latest arrival of the period was on 4 August 2026, 2 hours 3 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 4 August 2026 | 2 hours 3 minutes | Late-arriving aircraft |
| 13 June 2026 | 1 hour 51 minutes | Late-arriving aircraft |
| 24 June 2026 | 1 hour 48 minutes | Late-arriving aircraft |
| 1 May 2026 | 1 hour 46 minutes | Late-arriving aircraft |
| 16 May 2026 | 1 hour 46 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 79% of the 3,298 delay minutes carriers reported here, and the remaining four split what is left.
- 79%Late-arriving aircraft
- 18%Carrier
- 3%National Airspace System
79% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 3,298 reported delay minutes here, that single category outweighs weather by 79 to one. The split is drawn from 3,298 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.7% on time here.
Cancellations sit at 1.30% against a national 1.89%, which is ordinary. Diversions add another 0.43%.
Connections and stage length
What a delay here costs
8.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 45 minutes, which a normal layover absorbs.
The 508 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty.
The return leg is a different operation and performs like one: it runs 74.7% on time across 230 flights, 6 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 6 points of difference.
One caution: this is a thin sample. 231 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 Southwest on SAN to STS
Put together: treat all of this as provisional. 231 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 68.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 227 completed flights over 12 months sit behind that.
Related
Where to go next
- SAN to STS, every carrier
- Southwest on STS to SAN, the return leg
- SkyWest Airlines on SAN to STS80.1%
- Southwest Airlines network-wide record
- San Diego International (SAN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.