Carrier route record
WNSFO→LAX
Southwest Airlines · San Francisco to Los Angeles
- Flights
- 1,369
- Period
- July 2025 to June 2026
- Share of route
- 12%
- Carriers
- 8
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on SFO to LAX draws a D+. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 1,369 flights. The strongest carrier on the route with a full sample, United Airlines, flew 3,263 at 78.4% on time.
United Airlines is the most reliable of the five carriers covered here at 78.4% on time across 3,263 flights.
Key figures
On time
61.8%
Arrivals under 15 minutes late, of 1,361 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.58%
National rate is 1.81%
Whole route
73.9%
Every carrier on SFO to LAX, 11,015 flights
These figures cover 1,369 flights between July 2025 and June 2026. Beyond the headline rate, 12.9% 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 SFO to LAX
Southwest flew 1,369 of the 11,015 flights on SFO to LAX, about 12% of it. Its 61.8% on time is 12 points worse than the route as a whole, which runs 73.9%. Ranked by on-time rate it is number seven of eight carriers on the route, where the range runs from United at 78.4% to Envoy at 0.0%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. United Airlines arrives on time 78.4% of the time; Frontier Airlines manages 68.6%. Sample sizes sit next to every figure, because a two-point gap across 391 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 3,263 | 78.4% | 49 min | 0.28% | B+ |
| American Airlinesthin sample | 345 | 76.7% | 108 min | 0.29% | B+ |
| SkyWest Airlines | 2,588 | 76.6% | 60 min | 1.04% | B |
| Delta Air Lines | 2,373 | 73.6% | 65 min | 1.56% | C |
| Alaska Airlines | 685 | 69.7% | 47 min | 0.73% | C+ |
| Frontier Airlines | 391 | 68.6% | 84 min | 1.53% | C |
| Southwest Airlines (this page) | 1,369 | 61.8% | 60 min | 0.58% | D+ |
| Envoy Airthin sample | 1 | 0.0% | 35 min | 0.00% | F+ |
United leads Frontier by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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 62 points, against 10 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am279 flights93.9%
- 8am–11am156 flights70.5%
- 11am–2pm206 flights45.6%
- 2pm–5pm258 flights57.4%
- 5pm–8pm307 flights58.5%
- 8pm–5am163 flights31.7%
Scale runs 25% to 100%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 31.7% on time, against 93.9% for the 5am–8am 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 5pm–8pm window is the busiest, with 307 flights scheduled in it.
Across the year
Southwest on SFO to LAX through the year
June is the worst month at 34.6% on time, 49 points below January, the best at 83.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. June was the busiest month here, with 153 flights.
Across the week, Saturday is the strongest day at 71.7% on time and Monday the weakest at 54.6%. 17 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 72% of the 31,000 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.
- 72%Late-arriving aircraft
- 21%Carrier
- 6%National Airspace System
- 0%Extreme weather
72% 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 31,000 reported delay minutes here, that single category outweighs weather by 72 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 30,967 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.9% on time here.
Cancellations are rare at 0.58%, 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.9% 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 337 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 57.1% on time across 1,370 flights, 5 points below 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 5 points of difference.
The sample behind these figures is 1,369 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
What to do with this
Booking Southwest on SFO to LAX
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 83.8% on time and June 34.6%, a swing of 49 points. If the dates move at all, move them out of June before you think about anything else. 1,361 completed flights over 12 months sit behind that.
Related
Where to go next
- SFO to LAX, every carrier
- Southwest on LAX to SFO, the return leg
- United Airlines on SFO to LAX78.4%
- American Airlines on SFO to LAX76.7%
- SkyWest Airlines on SFO to LAX76.6%
- Delta Air Lines on SFO to LAX73.6%
- Alaska Airlines on SFO to LAX69.7%
- Frontier Airlines on SFO to LAX68.6%
- Southwest Airlines network-wide record
- San Francisco International (SFO) delay statistics
- Los Angeles International (LAX) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.