Carrier route record
WNLAS→SFO
Southwest Airlines · Las Vegas to San Francisco
- Flights
- 1,310
- Period
- July 2025 to June 2026
- Share of route
- 22%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on LAS to SFO earns an F+, which is as low as this site's scale goes for a reason. Only 48.8% of flights arrive inside the 15-minute window, 29 points worse than the national rate of 77.6%. Late arrivals average about 55 minutes. Treat any tight connection here as a coin flip. That rests on 1,310 flights. The strongest carrier on the route with a full sample, United Airlines, flew 2,756 at 67.5% on time.
United Airlines is the most reliable of the three carriers covered here at 67.5% on time across 2,756 flights.
Key figures
On time
48.8%
Arrivals under 15 minutes late, of 1,304 completed flights
Avg delay
54 min
Across delayed arrivals only, not all flights
Cancelled
0.38%
National rate is 1.81%
Whole route
62.8%
Every carrier on LAS to SFO, 6,060 flights
These figures cover 1,310 flights between July 2025 and June 2026. Beyond the headline rate, 15.0% 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 LAS to SFO
Southwest flew 1,310 of the 6,060 flights on LAS to SFO, about 22% of it. Its 48.8% on time is 14 points worse than the route as a whole, which runs 62.8%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from SkyWest at 100.0% to Southwest at 48.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The three carriers here are closely matched: 3 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 3 | 100.0% | — | 0.00% | A+ |
| United Airlines | 2,756 | 67.5% | 61 min | 0.44% | C+ |
| Alaska Airlines | 1,116 | 66.5% | 52 min | 1.08% | C |
| Frontier Airlines | 875 | 64.3% | 70 min | 1.37% | D |
| Southwest Airlines (this page) | 1,310 | 48.8% | 54 min | 0.38% | F+ |
No carrier stands out. United tops the table at 67.5%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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 20 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am50 flights58.0%
- 8am–11am315 flights54.7%
- 11am–2pm216 flights56.0%
- 2pm–5pm160 flights55.3%
- 5pm–8pm248 flights37.7%
- 8pm–5am321 flights42.4%
Scale runs 30% to 65%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 37.7% on time, against 58.0% 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 8pm–5am window is the busiest, with 321 flights scheduled in it.
Across the year
Southwest on LAS to SFO through the year
June is the worst month at 9.3% on time, 66 points below January, the best at 75.2%. 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. August was the busiest month here, with 119 flights.
Across the week, Saturday is the strongest day at 62.4% on time and Monday the weakest at 39.6%. 23 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. National Airspace System accounts for 43% of the 36,000 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.
- 43%National Airspace System
- 31%Late-arriving aircraft
- 24%Carrier
- 3%Extreme weather
- 0%Security
43% 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 16,000 minutes out of 36,000, against a national NAS share of 21%. The split is drawn from 36,150 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 58.0% on time here.
Cancellations are rare at 0.38%, 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. 15.0% 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 414 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 66.3% on time across 1,312 flights, 18 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 18 points of difference.
The sample behind these figures is 1,310 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 LAS to SFO
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 75.2% on time and June 9.3%, a swing of 66 points. If the dates move at all, move them out of June before you think about anything else. 1,304 completed flights over 12 months sit behind that.
Related
Where to go next
- LAS to SFO, every carrier
- Southwest on SFO to LAS, the return leg
- United Airlines on LAS to SFO67.5%
- Alaska Airlines on LAS to SFO66.5%
- Frontier Airlines on LAS to SFO64.3%
- Southwest Airlines network-wide record
- Harry Reid International (LAS) delay statistics
- San Francisco International (SFO) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- 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.