Carrier route record
WNMIA→AUS
Southwest Airlines · Miami to Austin
- Flights
- 348
- Period
- July 2025 to June 2026
- Share of route
- 16%
- Carriers
- 5
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on MIA to AUS sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.6%. The late ones land roughly 50 minutes behind schedule. That rests on 348 flights, with a median arrival 1 minute late.
The national on-time rate over the same period is 77.6%, so Southwest on MIA to AUS runs 8 points behind the country as a whole. Across a thousand flights that is about 84 extra late arrivals.
Key figures
On time
69.2%
Arrivals under 15 minutes late, of 347 completed flights
Avg delay
48 min
Across delayed arrivals only, not all flights
Cancelled
0.29%
National rate is 1.81%
Whole route
72.8%
Every carrier on MIA to AUS, 2,161 flights
These figures cover 348 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
Carrier by carrier
Southwest against every carrier on MIA to AUS
Southwest flew 348 of the 2,161 flights on MIA to AUS, about 16% of it. Its 69.2% on time is 4 points worse than the route as a whole, which runs 72.8%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from Frontier at 82.6% to Delta at 69.1%. Three 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 |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 46 | 82.6% | 97 min | 0.00% | B+ |
| American Airlines | 1,523 | 73.8% | 76 min | 1.31% | C |
| Envoy Airthin sample | 22 | 72.7% | 47 min | 0.00% | C+ |
| Southwest Airlines (this page)thin sample | 348 | 69.2% | 48 min | 0.29% | C+ |
| Delta Air Linesthin sample | 222 | 69.1% | 94 min | 0.90% | 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 51 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–8am5 flights—
- 8am–11am52 flights96.2%
- 11am–2pm177 flights66.1%
- 2pm–5pm83 flights67.1%
- 5pm–8pm31 flights45.2%
- 8pm–5am—
Scale runs 35% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 45.2% on time, against 96.2% 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 11am–2pm window is the busiest, with 177 flights scheduled in it.
Across the year
Southwest on MIA to AUS through the year
December is the weak month at 41.9% on time, against 83.3% in November. 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. January was the busiest month here, with 32 flights.
Across the week, Wednesday is the strongest day at 83.7% on time and Sunday the weakest at 53.8%. 30 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 5,153 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%National Airspace System
- 18%Carrier
- 5%Extreme weather
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 5,153 reported delay minutes here, that single category outweighs weather by 11 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 5,153 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 96.2% on time here.
Cancellations are rare at 0.29%, 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
6.9% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 50 minutes, which a normal layover absorbs.
The 1,103 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 runs 67.3% on time across 349 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 348 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 MIA to AUS
Put together: treat all of this as provisional. 348 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 69.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 347 completed flights over 12 months sit behind that.
Related
Where to go next
- MIA to AUS, every carrier
- Southwest on AUS to MIA, the return leg
- American Airlines on MIA to AUS73.8%
- Delta Air Lines on MIA to AUS69.1%
- Southwest Airlines network-wide record
- Miami International (MIA) 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.