Carrier route record
WNLAS→SLC
Southwest Airlines · Las Vegas to Salt Lake City
- Flights
- 1,443
- Period
- July 2025 to June 2026
- Share of route
- 39%
- 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 SLC lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That is a workable record, not a spotless one. That rests on 1,443 flights. The strongest carrier on the route with a full sample, Frontier Airlines, flew 514 at 89.5% on time.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on LAS to SLC from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.5%
Arrivals under 15 minutes late, of 1,436 completed flights
Avg delay
51 min
Across delayed arrivals only, not all flights
Cancelled
0.49%
National rate is 1.81%
Whole route
82.8%
Every carrier on LAS to SLC, 3,741 flights
These figures cover 1,443 flights between July 2025 and June 2026. The median arrival is 4 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Southwest against every carrier on LAS to SLC
Southwest flew 1,443 of the 3,741 flights on LAS to SLC, about 39% of it. Its 76.5% on time is 6 points worse than the route as a whole, which runs 82.8%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from Frontier at 89.5% to Southwest at 76.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two 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 |
|---|---|---|---|---|---|
| Frontier Airlines | 514 | 89.5% | 76 min | 1.36% | A |
| Delta Air Lines | 1,713 | 86.4% | 71 min | 0.58% | A+ |
| SkyWest Airlinesthin sample | 5 | 80.0% | 37 min | 0.00% | B+ |
| Spirit Airlinesthin sample | 66 | 76.6% | 97 min | 3.03% | B− |
| Southwest Airlines (this page) | 1,443 | 76.5% | 51 min | 0.49% | B+ |
No carrier stands out. Frontier tops the table at 89.5%, 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 27 points, against 3 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am188 flights89.9%
- 8am–11am221 flights89.1%
- 11am–2pm257 flights82.5%
- 2pm–5pm260 flights70.5%
- 5pm–8pm205 flights70.9%
- 8pm–5am312 flights63.2%
Scale runs 55% to 95%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 63.2% on time, against 89.9% 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 8pm–5am window is the busiest, with 312 flights scheduled in it.
Across the year
Southwest on LAS to SLC through the year
June is the worst month at 59.8% on time, 25 points below January, the best at 85.0%. 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. March was the busiest month here, with 134 flights.
Across the week, Saturday is the strongest day at 86.8% on time and Sunday the weakest at 67.6%. 19 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 66% of the 17,000 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.
- 66%Late-arriving aircraft
- 28%Carrier
- 6%National Airspace System
- 0%Extreme weather
66% 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 17,000 reported delay minutes here, that single category outweighs weather by 66 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 17,063 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 89.9% on time here.
Cancellations are rare at 0.49%, 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
6.4% 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 50 minutes, which a normal layover absorbs.
At 368 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 runs 75.2% on time across 1,442 flights, within about a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,443 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 SLC
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 85.0% on time and June 59.8%, a swing of 25 points. If the dates move at all, move them out of June before you think about anything else. 1,436 completed flights over 12 months sit behind that.
Related
Where to go next
- LAS to SLC, every carrier
- Southwest on SLC to LAS, the return leg
- Frontier Airlines on LAS to SLC89.5%
- Delta Air Lines on LAS to SLC86.4%
- Southwest Airlines network-wide record
- Harry Reid International (LAS) delay statistics
- Salt Lake City International (SLC) 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.