Carrier route record
WNSLC→LGB
Southwest Airlines · Salt Lake City to Long Beach
- Flights
- 480
- Period
- September 2025 to August 2026
- Share of route
- 31%
- Carriers
- 3
Historical statistics for September 2025 to August 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 77.3%. About one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That rests on 480 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 559 at 92.7% on time.
The US average over the same twelve months is 77.3%, 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
76.6%
Arrivals under 15 minutes late, of 479 completed flights
Avg delay
42 min
Across delayed arrivals only, not all flights
Cancelled
0.21%
National rate is 1.89%
Whole route
86.2%
Every carrier on SLC to LGB, 1,569 flights
These figures cover 480 flights between September 2025 and August 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.
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Carrier by carrier
Southwest against every carrier on SLC to LGB
Southwest flew 480 of the 1,569 flights on SLC to LGB, about 31% of it. Its 76.6% on time is 10 points worse than the route as a whole, which runs 86.2%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 92.7% to Southwest at 76.6%.
The two carriers here are closely matched: 5 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 | 559 | 92.7% | 51 min | 0.00% | A+ |
| Delta Air Lines | 530 | 88.2% | 57 min | 0.94% | A+ |
| Southwest Airlines (this page) | 480 | 76.6% | 42 min | 0.21% | B+ |
No carrier stands out. SkyWest tops the table at 92.7%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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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 28 points, against 5 points between the best and worst carrier.
- 5am–8am9 flights—
- 8am–11am91 flights81.3%
- 11am–2pm129 flights86.0%
- 2pm–5pm44 flights75.0%
- 5pm–8pm171 flights70.0%
- 8pm–5am36 flights58.3%
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 58.3% on time, against 86.0% for the 11am–2pm 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 171 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 89.1% on time and Sunday the weakest at 67.1%, a spread of 22 points.
Arrival by arrival
How late Southwest on SLC to LGB runs when it is late
The 112 late arrivals split 47 under half an hour, 46 between 30 and 60 minutes, and 19 an hour or more.
- 15+ min early101 flights21.1%
- Within 15 min266 flights55.5%
- 15–29 min late47 flights9.8%
- 30–59 min late46 flights9.6%
- 1–2 hours late18 flights3.8%
- 2+ hours late1 flights0.2%
Scale runs 0% to 100%.
Share of 479 completed flights by arrival against schedule.
36 of 141 late departures made up the time and arrived on time, 26% of them. Only 7 left on time and still arrived late.
The worst days
Worst days for Southwest on SLC to LGB
The latest arrival of the period was on 29 April 2026, 3 hours 10 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on five of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 29 April 2026 | 3 hours 10 minutes | Late-arriving aircraft |
| 23 July 2026 | 1 hour 59 minutes | Late-arriving aircraft |
| 20 February 2026 | 1 hour 56 minutes | Late-arriving aircraft |
| 24 November 2025 | 1 hour 55 minutes | Late-arriving aircraft |
| 13 August 2026 | 1 hour 54 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 72% of the 4,646 delay minutes carriers reported here, and the remaining four split what is left.
- 72%Late-arriving aircraft
- 18%Carrier
- 9%National Airspace System
- 1%Extreme weather
72% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,646 reported delay minutes here, that single category outweighs weather by 72 to one. The split is drawn from 4,646 reported delay minutes.
Cancellations are rare at 0.21%, below the national 1.89% 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 4.0% land an hour or more behind schedule, against 8.3% 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.
The return leg is a different operation and performs like one: it runs 85.1% on time across 480 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. 480 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. 480 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 76.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 479 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 LGB92.7%
- Delta Air Lines on SLC to LGB88.2%
- 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 7.05 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.