Carrier route record
UADEN→TUS
United Airlines · Denver to Tucson
- Flights
- 836
- Period
- July 2025 to June 2026
- Share of route
- 30%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on DEN to TUS lands a B+, 3 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 836 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 622 at 84.3% on time.
The US average over the same twelve months is 77.6%, so there is little to separate United on DEN to TUS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.6%
Arrivals under 15 minutes late, of 834 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.12%
National rate is 1.81%
Whole route
77.1%
Every carrier on DEN to TUS, 2,755 flights
These figures cover 836 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
United against every carrier on DEN to TUS
United flew 836 of the 2,755 flights on DEN to TUS, about 30% of it. Its 80.6% on time is 4 points better than the route as a whole, which runs 77.1%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from SkyWest at 84.3% to Southwest at 70.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 84.3% of the time; Southwest Airlines manages 70.6%. Sample sizes sit next to every figure, because a two-point gap across 1,202 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 622 | 84.3% | 76 min | 0.48% | B+ |
| Frontier Airlinesthin sample | 95 | 81.9% | 50 min | 1.05% | B |
| United Airlines (this page) | 836 | 80.6% | 57 min | 0.12% | B+ |
| Southwest Airlines | 1,202 | 70.6% | 50 min | 0.42% | C+ |
The spread between SkyWest and Southwest is 14 points, wide enough that it should decide the booking. On a hundred trips that is 14 more arrivals inside the on-time window.
Flight by flight
United flight numbers on DEN to TUS
Departure window
When United runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 14 points, against 14 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am—
- 11am–2pm382 flights86.4%
- 2pm–5pm161 flights84.4%
- 5pm–8pm274 flights72.9%
- 8pm–5am19 flights—
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 86.4% on time, ahead of 5pm–8pm at 72.9%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 11am–2pm window is the busiest, with 382 flights scheduled in it.
Across the year
United on DEN to TUS through the year
June is the worst month at 63.3% on time, 25 points below November, the best at 88.6%. 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. October was the busiest month here, with 93 flights.
Across the week, Tuesday is the strongest day at 89.4% on time and Friday the weakest at 73.3%. 16 points is a smaller lever than departure hour, but it is free.
Delay causes
Why United runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 54% of the 9,208 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
- 33%Carrier
- 12%National Airspace System
- 1%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 9,208 reported delay minutes here, that single category outweighs weather by 54 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 9,208 reported delay minutes.
Cancellations are rare at 0.12%, 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
6.7% 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 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. 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 84.7% on time across 836 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 836 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 United on DEN to TUS
Put together: treat all of this as provisional. 836 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 80.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 834 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to TUS, every carrier
- United on TUS to DEN, the return leg
- SkyWest Airlines on DEN to TUS84.3%
- Southwest Airlines on DEN to TUS70.6%
- United Airlines network-wide record
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
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.