Carrier route record
WNSLC→LGB
Southwest Airlines · Salt Lake City to Long Beach
- Flights
- 463
- Period
- July 2025 to June 2026
- Share of route
- 30%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on SLC to LGB lands a B+, level with the national rate of 77.6%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about 40 minutes on average. That is a workable record, not a spotless one. That rests on 463 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 621 at 93.5% on time.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on SLC to LGB from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
77.3%
Arrivals under 15 minutes late, of 462 completed flights
Avg delay
40 min
Across delayed arrivals only, not all flights
Cancelled
0.22%
National rate is 1.81%
Whole route
87.4%
Every carrier on SLC to LGB, 1,552 flights
These figures cover 463 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 SLC to LGB
Southwest flew 463 of the 1,552 flights on SLC to LGB, about 30% of it. Its 77.3% on time is 10 points worse than the route as a whole, which runs 87.4%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 93.5% to Southwest at 77.3%.
The two carriers here are closely matched: 4 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 Airlines | 621 | 93.5% | 42 min | 0.00% | A+ |
| Delta Air Lines | 468 | 89.2% | 61 min | 0.64% | A+ |
| Southwest Airlines (this page) | 463 | 77.3% | 40 min | 0.22% | B+ |
No carrier stands out. SkyWest tops the table at 93.5%, 4 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 16 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am5 flights—
- 8am–11am68 flights75.0%
- 11am–2pm149 flights86.6%
- 2pm–5pm54 flights70.4%
- 5pm–8pm163 flights74.1%
- 8pm–5am24 flights—
Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 86.6% on time, ahead of 2pm–5pm at 70.4%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 5pm–8pm window is the busiest, with 163 flights scheduled in it.
Across the year
Southwest on SLC to LGB through the year
December is the weak month at 61.5% on time, against 94.1% in September. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. February was the busiest month here, with 46 flights.
Across the week, Saturday is the strongest day at 92.7% on time and Sunday the weakest at 68.1%. 25 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 67% of the 4,151 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.
- 67%Late-arriving aircraft
- 22%Carrier
- 10%National Airspace System
67% 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 4,151 reported delay minutes here, that single category outweighs weather by 67 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 4,151 reported delay minutes.
Cancellations are rare at 0.22%, 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
Badly late arrivals are rare here: only 3.5% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 588 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 86.3% on time across 463 flights, 9 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 9 points of difference.
One caution: this is a thin sample. 463 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 SLC to LGB
Put together: treat all of this as provisional. 463 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 77.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 462 completed flights over 12 months sit behind that.
Related
Where to go next
- SLC to LGB, every carrier
- Southwest on LGB to SLC, the return leg
- SkyWest Airlines on SLC to LGB93.5%
- Delta Air Lines on SLC to LGB89.2%
- Southwest Airlines network-wide record
- 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.