Route reliability record
DEN→TUS
Denver to Tucson
- Flights
- 2,708
- Period
- September 2025 to August 2026
- Distance
- 639 mi
- Carriers
- 4
This route lands a B+, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 2,708 DEN to TUS flights, of which SkyWest Airlines flew 524 at 86.6% on time.
Best time to fly DEN to TUS: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 88.8% of the time and Tuesday flights 85.8%, against 76.9% for the route overall.
SkyWest Airlines is the most reliable of the three carriers covered here at 86.6% on time across 524 flights.
Key figures
On time
76.9%
Arrivals under 15 minutes late, of 2,693 completed flights
Avg delay
56 min
Across delayed arrivals only, not all flights
Cancelled
0.37%
National rate is 1.89%
Best carrier
SkyWest
86.6% on time across 524 flights
These figures cover 2,708 flights between September 2025 and August 2026. The median arrival is 4 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 DEN to TUS
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 86.6% of the time; Southwest Airlines manages 71.1%. Sample sizes sit next to every figure, because a two-point gap across 1,184 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 524 | 86.6% | 56 min | 0.38% | A+ |
| Frontier Airlinesthin sample | 77 | 78.9% | 49 min | 1.30% | B |
| United Airlines | 923 | 78.7% | 63 min | 0.22% | B+ |
| Southwest Airlines | 1,184 | 71.1% | 52 min | 0.42% | C+ |
The spread between SkyWest and Southwest is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 more arrivals inside the on-time window.
Flight by flight
Flights on DEN to TUS
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 Denver to Tucson
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. DEN → TUSDenver to Tucson | SkyWest Airlines | 86.3% | 86.6% | 0.38% | 2pm–5pm, Tue | — |
| 2. DEN → TUSDenver to Tucson | United Airlines | 78.5% | 78.7% | 0.22% | 11am–2pm, Tue | UA 1762 19:10 |
| 3. DEN → TUSDenver to Tucson | Southwest Airlines | 70.8% | 71.1% | 0.42% | 8am–11am, Tue | — |
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 27 points, against 16 points between the best and worst carrier.
- 5am–8am221 flights85.8%
- 8am–11am388 flights88.8%
- 11am–2pm582 flights84.9%
- 2pm–5pm639 flights78.3%
- 5pm–8pm518 flights63.9%
- 8pm–5am360 flights62.3%
Scale runs 55% to 95%.
The 8pm–5am window is where this operation falls apart: 62.3% on time, against 88.8% 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 639 flights scheduled in it.
Explore
Filter DEN to TUS 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 DEN to TUS, the best departure window is 8am–11am at 88.8% on time and the worst is 8pm–5am at 62.3%, a wide gap of 26.5 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am85.8%
- 8–11am88.8%
- 11am–2pm84.9%
- 2–5pm78.3%
- 5–8pm63.9%
- 8pm–5am62.3%
best all US flightsScale 55% to 95%.
Across the year
When delays peak on this route
This route's year swings by 28 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 61.4% on time, 28 points below November, the best at 89.1%. 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 275 flights.
Across the week, Tuesday is the strongest day at 85.8% on time and Sunday the weakest at 72.1%, a spread of 14 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 52% of the 35,000 delay minutes carriers reported here, and the remaining four split what is left.
- 52%Late-arriving aircraft
- 34%Carrier
- 13%National Airspace System
- 1%Extreme weather
- 0%Security
52% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 35,000 reported delay minutes here, that single category outweighs weather by 51 to one. The split is drawn from 34,847 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 88.8% on time here.
Cancellations are rare at 0.37%, 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
7.1% 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 about an hour, which a normal layover absorbs.
The 639 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 83.9% on time across 2,719 flights, 7 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 7 points of difference.
The sample behind these figures is 2,708 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 TUS 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. November runs 89.1% on time and June 61.4%, a swing of 28 points. If the dates move at all, move them out of June before you think about anything else. 2,693 completed flights over 12 months sit behind that.
Common questions
DEN to TUS questions
How often is DEN to TUS delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 23.1% of the 2,708 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DEN to TUS?
SkyWest Airlines leads at 86.6% on time across 524 flights. Southwest Airlines is at the other end on 71.1%, a gap of 16 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 DEN to TUS?
The 8am–11am departure window is the strongest at 88.8% on time. The 8pm–5am window is the weakest at 62.3%, 27 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 DEN to TUS?
June is the weakest month at 61.4% on time, compared with 89.1% in November. Across the year that is 28 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
- TUS to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- SkyWest Airlines on DEN to TUS86.6%
- United Airlines on DEN to TUS78.7%
- Southwest Airlines on DEN to TUS71.1%
- DEN to PHX, a related route75.6%
- PHX to TUS, a related route81.0%
- DEN to SLC, a related route78.2%
- SkyWest Airlines on-time record86.6%
- Frontier Airlines on-time record78.9%
- United Airlines on-time record78.7%
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
Direction matters. DEN to TUS and TUS to DEN 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.