Carrier route record
WNSLC→AUS
Southwest Airlines · Salt Lake City to Austin
- Flights
- 470
- Period
- July 2025 to June 2026
- Share of route
- 26%
- 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 AUS lands a B+, level with the national rate of 77.6%. Roughly one flight in five 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 470 flights, with a median arrival 3 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on SLC to AUS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.2%
Arrivals under 15 minutes late, of 467 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.64%
National rate is 1.81%
Whole route
82.1%
Every carrier on SLC to AUS, 1,783 flights
These figures cover 470 flights between July 2025 and June 2026. The median arrival is 3 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 AUS
Southwest flew 470 of the 1,783 flights on SLC to AUS, about 26% of it. Its 78.2% on time is 4 points worse than the route as a whole, which runs 82.1%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 87.8% to Southwest at 78.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 232 | 87.8% | 53 min | 0.86% | A+ |
| Delta Air Lines | 1,081 | 82.6% | 66 min | 0.56% | B+ |
| Southwest Airlines (this page) | 470 | 78.2% | 50 min | 0.64% | B+ |
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 57 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am78 flights97.4%
- 8am–11am75 flights86.7%
- 11am–2pm153 flights77.8%
- 2pm–5pm97 flights76.0%
- 5pm–8pm44 flights40.9%
- 8pm–5am23 flights—
Scale runs 30% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 40.9% on time, against 97.4% 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 11am–2pm window is the busiest, with 153 flights scheduled in it.
Across the year
Southwest on SLC to AUS through the year
June is the worst month at 57.1% on time, 40 points below September, the best at 96.7%. 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. July was the busiest month here, with 53 flights.
Across the week, Monday is the strongest day at 85.7% on time and Sunday the weakest at 71.7%. 14 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 54% of the 5,061 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.
- 54%Late-arriving aircraft
- 23%Carrier
- 23%National Airspace System
- 0%Extreme weather
- 0%Security
54% 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 5,061 reported delay minutes here, that single category outweighs weather by 54 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 5,061 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 97.4% on time here.
Cancellations are rare at 0.64%, 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 3.4% 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 1,086 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 70.6% on time across 470 flights, 8 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 8 points of difference.
One caution: this is a thin sample. 470 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 AUS
Put together: treat all of this as provisional. 470 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 78.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 467 completed flights over 12 months sit behind that.
Related
Where to go next
- SLC to AUS, every carrier
- Southwest on AUS to SLC, the return leg
- SkyWest Airlines on SLC to AUS87.8%
- Delta Air Lines on SLC to AUS82.6%
- Southwest Airlines network-wide record
- Salt Lake City International (SLC) delay statistics
- Austin-Bergstrom International (AUS) 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.