Carrier route record
WNSAN→STS
Southwest Airlines · San Diego to Santa Rosa
- Flights
- 133
- Period
- July 2025 to June 2026
- Share of route
- 14%
- Carriers
- 2
Historical statistics for July 2025 to June 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, 8 points worse than the national rate of 77.6%. The late ones land about 45 minutes behind schedule. That rests on 133 flights, with a median arrival 2 minutes early.
The national on-time rate over the same period is 77.6%, so Southwest on SAN to STS runs 8 points behind the country as a whole. Across a thousand flights that is about 79 extra late arrivals.
Key figures
On time
69.7%
Arrivals under 15 minutes late, of 132 completed flights
Avg delay
45 min
Across delayed arrivals only, not all flights
Cancelled
0.75%
National rate is 1.81%
Whole route
78.8%
Every carrier on SAN to STS, 960 flights
These figures cover 133 flights between July 2025 and June 2026. Beyond the headline rate, 8.3% 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
Southwest against every carrier on SAN to STS
Southwest flew 133 of the 960 flights on SAN to STS, about 14% of it. Its 69.7% on time is 9 points worse than the route as a whole, which runs 78.8%. Ranked by on-time rate it is last of two carriers on the route, where the range runs from SkyWest at 80.3% to Southwest at 69.7%.
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 | 827 | 80.3% | 48 min | 3.39% | B− |
| Southwest Airlines (this page)thin sample | 133 | 69.7% | 45 min | 0.75% | C+ |
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 34 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–8am—
- 8am–11am48 flights91.7%
- 11am–2pm—
- 2pm–5pm—
- 5pm–8pm8 flights—
- 8pm–5am77 flights57.9%
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 57.9% 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 77 flights scheduled in it.
Across the year
Southwest on SAN to STS through the year
- Apr–Jun 2026133 flights69.7%
Scale runs 60% to 75%. 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 69.7% on time across 133 flights.
Split by quarter, Southwest on SAN to STS logged 133 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 69.7% annual figure is the one to use.
Delay causes
Why Southwest runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 75% of the 1,806 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.
- 75%Late-arriving aircraft
- 23%Carrier
- 2%National Airspace System
75% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 1,806 reported delay minutes here, that single category outweighs weather by 75 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 1,806 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 are rare at 0.75%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
8.3% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 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. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg is a different operation and performs like one: it runs 80.3% on time across 132 flights, 11 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 11 points of difference.
One caution: this is a thin sample. 133 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. 133 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 69.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 132 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 STS80.3%
- 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 7.04 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.