Carrier route record
WNAUS→SLC
Southwest Airlines · Austin to Salt Lake City
- Flights
- 482
- Period
- September 2025 to August 2026
- Share of route
- 27%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on AUS to SLC sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 482 flights, with a median arrival 2 minutes late.
The national on-time rate over the same period is 77.3%, so Southwest on AUS to SLC runs 9 points behind the country as a whole. Across a thousand flights that is about 93 extra late arrivals.
Key figures
On time
68.0%
Arrivals under 15 minutes late, of 481 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
0.21%
National rate is 1.89%
Whole route
81.1%
Every carrier on AUS to SLC, 1,798 flights
These figures cover 482 flights between September 2025 and August 2026. Beyond the headline rate, 9.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Southwest against every carrier on AUS to SLC
Southwest flew 482 of the 1,798 flights on AUS to SLC, about 27% of it. Its 68.0% on time is 13 points worse than the route as a whole, which runs 81.1%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Delta at 86.0% to Southwest at 68.0%. 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 |
|---|---|---|---|---|---|
| Delta Air Lines | 1,072 | 86.0% | 94 min | 0.84% | A+ |
| SkyWest Airlinesthin sample | 244 | 85.8% | 82 min | 1.23% | A |
| Southwest Airlines (this page) | 482 | 68.0% | 58 min | 0.21% | C+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 31 points, against half a point between the best and worst carrier.
- 5am–8am20 flights—
- 8am–11am106 flights81.9%
- 11am–2pm35 flights80.0%
- 2pm–5pm170 flights67.6%
- 5pm–8pm127 flights51.2%
- 8pm–5am24 flights—
Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 51.2% on time, against 81.9% for the 8am–11am 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 2pm–5pm window is the busiest, with 170 flights scheduled in it.
Across the year
Southwest on AUS to SLC through the year
June is the worst month at 44.9% on time, 39 points below February, the best at 83.7%. 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 54 flights.
Across the week, Friday is the strongest day at 73.2% on time and Saturday the weakest at 45.5%, a spread of 28 points.
Arrival by arrival
How late Southwest on AUS to SLC runs when it is late
The 154 late arrivals split 58 under half an hour, 49 between 30 and 60 minutes, and 47 an hour or more.
- 15+ min early66 flights13.7%
- Within 15 min261 flights54.3%
- 15–29 min late58 flights12.1%
- 30–59 min late49 flights10.2%
- 1–2 hours late26 flights5.4%
- 2+ hours late21 flights4.4%
Scale runs 0% to 100%.
Share of 481 completed flights by arrival against schedule.
49 of 186 late departures made up the time and arrived on time, 26% of them. 17 flights left on time and still arrived late.
The worst days
Worst days for Southwest on AUS to SLC
The latest arrival of the period was on 4 January 2026, 6 hours 4 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). On four of the five worst days the largest share was filed as a late-arriving aircraft.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 4 January 2026 | 6 hours 4 minutes | Carrier |
| 26 January 2026 | 3 hours 57 minutes | Late-arriving aircraft |
| 4 December 2025 | 3 hours 27 minutes | Late-arriving aircraft |
| 25 July 2026 | 3 hours 23 minutes | Late-arriving aircraft |
| 12 June 2026 | 3 hours 14 minutes | Late-arriving aircraft |
Delay causes
Why Southwest runs late on this route
Late-arriving aircraft accounts for 69% of the 8,939 delay minutes carriers reported here, and the remaining four split what is left.
- 69%Late-arriving aircraft
- 24%Carrier
- 6%National Airspace System
- 0%Extreme weather
69% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 8,939 reported delay minutes here, that single category outweighs weather by 69 to one. The split is drawn from 8,939 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 81.9% on time here.
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
9.8% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
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.
The return leg is a different operation and performs like one: it runs 76.2% on time across 482 flights, 8 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 8 points of difference.
One caution: this is a thin sample. 482 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 AUS to SLC
Put together: treat all of this as provisional. 482 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 68.0% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 481 completed flights over 12 months sit behind that.
Related
Where to go next
- AUS to SLC, every carrier
- Southwest on SLC to AUS, the return leg
- Delta Air Lines on AUS to SLC86.0%
- SkyWest Airlines on AUS to SLC85.8%
- Southwest Airlines network-wide record
- Austin-Bergstrom International (AUS) delay statistics
- Salt Lake City International (SLC) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.