Route reliability record
AUS→SLC
Austin to Salt Lake City
- Flights
- 1,798
- Period
- September 2025 to August 2026
- Distance
- 1,086 mi
- Carriers
- 3
This route lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 1,798 AUS to SLC flights, of which Delta Air Lines flew 1,072 at 86.0% on time.
Best time to fly AUS to SLC: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 91.9% of the time and Tuesday flights 84.4%, against 81.1% for the route overall.
The US average over the same twelve months is 77.3%, 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.
Key figures
On time
81.1%
Arrivals under 15 minutes late, of 1,784 completed flights
Avg delay
76 min
Across delayed arrivals only, not all flights
Cancelled
0.72%
National rate is 1.89%
Best carrier
Delta
86.0% on time across 1,072 flights
These figures cover 1,798 flights between September 2025 and August 2026. The median arrival is 6 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.
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Carrier by carrier
Which airline is most reliable on AUS to SLC
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.0% of the time; Southwest Airlines manages 68.0%. Sample sizes sit next to every figure, because a two-point gap across 482 flights means less than a ten-point one.
| 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 | 482 | 68.0% | 58 min | 0.21% | C+ |
The spread between Delta and Southwest is 18 points, wide enough that it should decide the booking. On a hundred trips that is 18 more arrivals inside the on-time window.
Flight by flight
Flights on AUS to SLC
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Austin to Salt Lake City
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. AUS → SLCAustin to Salt Lake City | Delta Air Lines | 85.3% | 86.0% | 0.84% | 8am–11am, Tue | DL 2618 08:15 |
| 2. AUS → SLCAustin to Salt Lake City | Southwest Airlines | 67.9% | 68.0% | 0.21% | 8am–11am, Fri | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 19 points, against 18 points between the best and worst carrier.
- 5am–8am183 flights89.9%
- 8am–11am423 flights91.9%
- 11am–2pm381 flights82.5%
- 2pm–5pm303 flights74.5%
- 5pm–8pm483 flights72.9%
- 8pm–5am25 flights—
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 91.9% of the time, against 72.9% for the evening window. That is 19 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 483 flights scheduled in it.
Explore
Filter AUS to SLC by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On AUS to SLC, the best departure window is 8am–11am at 91.9% on time and the worst is 5pm–8pm at 72.9%, a wide gap of 19.0 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am89.9%
- 8–11am91.9%
- 11am–2pm82.5%
- 2–5pm74.5%
- 5–8pm72.9%
- 8pm–5am—
best all US flightsScale 60% to 95%. Cells under 30 flights show a dash.
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.
June is the worst month at 71.2% on time, 20 points below September, the best at 91.1%. 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 170 flights.
Across the week, Tuesday is the strongest day at 84.4% on time and Thursday the weakest at 76.7%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carrier accounts for 45% of the 26,000 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Carrier
- 45%Late-arriving aircraft
- 7%National Airspace System
- 3%Extreme weather
- 0%Security
45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 26,000 reported delay minutes here, that single category outweighs weather by 18 to one. The split is drawn from 25,665 reported delay minutes.
The largest share of delay minutes, 45%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 12,000 of the 26,000 delay minutes reported here.
Cancellations are rare at 0.72%, 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 actually costs
6.8% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last a little over an hour, which a normal layover absorbs.
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 runs 81.5% on time across 1,796 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,798 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.
Work out the risk of missing a connection in SLC after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 91.1% on time and June 71.2%, a swing of 20 points. If the dates move at all, move them out of June before you think about anything else. 1,784 completed flights over 12 months sit behind that.
Common questions
AUS to SLC questions
How often is AUS to SLC delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 18.9% of the 1,798 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on AUS to SLC?
Delta Air Lines leads at 86.0% on time across 1,072 flights. Southwest Airlines is at the other end on 68.0%, a gap of 18 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on AUS to SLC?
The 8am–11am departure window is the strongest at 91.9% on time. The 5pm–8pm window is the weakest at 72.9%, 19 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 June delays on AUS to SLC?
June is the weakest month at 71.2% on time, compared with 91.1% in September. 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.
Related
Where to go next
- SLC to AUS — the return legseparate record
- Austin-Bergstrom International (AUS) delay statistics
- Salt Lake City International (SLC) delay statistics
- Delta Air Lines on AUS to SLC86.0%
- SkyWest Airlines on AUS to SLC85.8%
- Southwest Airlines on AUS to SLC68.0%
- AUS to DEN, a related route78.9%
- DEN to SLC, a related route78.2%
- AUS to DFW, a related route74.9%
- Delta Air Lines on-time record86.0%
- SkyWest Airlines on-time record85.8%
- Southwest Airlines on-time record68.0%
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
Direction matters. AUS to SLC and SLC to AUS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.