Carrier route record
WNAUS→SLC
Southwest Airlines · Austin to Salt Lake City
- 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 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, 7 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 470 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.6%, so Southwest on AUS to SLC runs 7 points behind the country as a whole. Across a thousand flights that is about 70 extra late arrivals.
Key figures
On time
70.6%
Arrivals under 15 minutes late, of 469 completed flights
Avg delay
58 min
Across delayed arrivals only, not all flights
Cancelled
0.21%
National rate is 1.81%
Whole route
82.4%
Every carrier on AUS to SLC, 1,784 flights
These figures cover 470 flights between July 2025 and June 2026. Beyond the headline rate, 9.2% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Southwest against every carrier on AUS to SLC
Southwest flew 470 of the 1,784 flights on AUS to SLC, about 26% of it. Its 70.6% on time is 12 points worse than the route as a whole, which runs 82.4%. 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 70.6%. 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 | 233 | 87.8% | 72 min | 1.29% | A |
| Delta Air Lines | 1,081 | 86.5% | 93 min | 0.74% | A+ |
| Southwest Airlines (this page) | 470 | 70.6% | 58 min | 0.21% | C+ |
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 30 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–8am8 flights—
- 8am–11am96 flights81.1%
- 11am–2pm37 flights89.2%
- 2pm–5pm189 flights69.8%
- 5pm–8pm125 flights59.2%
- 8pm–5am15 flights—
Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 59.2% on time, against 89.2% 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 2pm–5pm window is the busiest, with 189 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 53 flights.
Across the week, Friday is the strongest day at 77.9% on time and Saturday the weakest at 54.5%. 23 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 62% of the 7,937 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.
- 62%Late-arriving aircraft
- 30%Carrier
- 7%National Airspace System
- 0%Security
- 0%Extreme weather
62% 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 7,937 reported delay minutes here, that single category outweighs weather by 62 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 7,937 reported delay minutes.
Cancellations are rare at 0.21%, 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
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 9.2% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum 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. 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 78.2% on time across 470 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. 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 AUS to SLC
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 70.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 469 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
- SkyWest Airlines on AUS to SLC87.8%
- Delta Air Lines on AUS to SLC86.5%
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.