Route reliability record

AUS→MIA

Austin to Miami

Flights: 2,161
Period: July 2025 to June 2026
Distance: 1,103 mi
Carriers: 6

This route lands a B, about a point better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 2,161 flights, with a median arrival 7 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

78.5%

Arrivals under 15 minutes late, of 2,130 completed flights

Avg delay

73 min

Across delayed arrivals only, not all flights

Cancelled

1.25%

National rate is 1.81%

Best carrier

American

79.8% on time across 1,522 flights

These figures cover 2,161 flights between July 2025 and June 2026. The median arrival is 7 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

Which airline is most reliable on AUS to MIA

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.

On-time performance by carrier on AUS to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	1	100.0%	—	0.00%	A+
Delta Air Linesthin sample	221	89.4%	84 min	1.36%	A
American Airlines	1,522	79.8%	82 min	1.38%	B
Envoy Airthin sample	22	72.7%	61 min	0.00%	C+
Frontier Airlinesthin sample	46	71.7%	82 min	0.00%	C+
Southwest Airlinesthin sample	349	67.3%	47 min	0.86%	C+

Departure window

The best time of day to leave

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. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am689 flights90.1%
8am–11am462 flights84.8%
11am–2pm453 flights74.5%
2pm–5pm178 flights59.0%
5pm–8pm377 flights64.0%
8pm–5am2 flights—

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 90.1% of the time, against 59.0% for the afternoon window. That is 31 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 689 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 20 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.

Darker means more delays. Figures are on-time percentages.February best, August worst

August is the worst month at 65.2% on time, 20 points below February, the best at 85.6%. 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. March was the busiest month here, with 217 flights.

Across the week, Tuesday is the strongest day at 85.8% 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 this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 45% of the 33,000 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.

Late-arriving aircraft
45%
Carrier
35%
National Airspace System
17%
Extreme weather
3%
Security
1%

45% 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 33,000 reported delay minutes here, that single category outweighs weather by 17 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 33,429 reported delay minutes.

The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 12,000 of the 33,000 delay minutes reported here.

Cancellations sit at 1.25% against a national 1.81%, which is ordinary. Diversions add another 0.19%.

Connections and stage length

What a delay here actually costs

7.1% 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 are the a little over an hour kind, 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 is a different operation and performs like one: it runs 72.8% on time across 2,161 flights, 6 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 6 points of difference.

The sample behind these figures is 2,161 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. February runs 85.6% on time and August 65.2%, a swing of 20 points. If the dates move at all, move them out of August before you think about anything else. 2,130 completed flights over 12 months sit behind that.

Common questions

AUS to MIA questions

How often is AUS to MIA delayed?

About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.5% of the 2,161 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

How reliable is AUS to MIA compared with the rest of the country?

78.5% of flights arrive on time here against a national 77.6%, a difference of about a point in its favour. That is worth a B on this site's grading scale.

What time of day has the fewest delays on AUS to MIA?

The 5am–8am departure window is the strongest at 90.1% on time. The 2pm–5pm window is the weakest at 59.0%, 31 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are August delays on AUS to MIA?

August is the weakest month at 65.2% on time, compared with 85.6% in February. Across the year that is 20 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. AUS to MIA and MIA to AUS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures