Carrier route record
UAPHX→DEN
United Airlines · Phoenix to Denver
- Flights
- 2,370
- Period
- July 2025 to June 2026
- Share of route
- 27%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on PHX to DEN lands a B+, 6 points better than the national rate of 77.6%. About one flight in six arrives 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 2,370 flights. The strongest carrier on the route with a full sample, Frontier Airlines, flew 1,427 at 80.0% on time.
Set against the rest of the country, United's PHX to DEN record is 6 points better than the US average of 77.6%. That gap is worth roughly 59 fewer late arrivals for every thousand flights.
Key figures
On time
83.5%
Arrivals under 15 minutes late, of 2,347 completed flights
Avg delay
75 min
Across delayed arrivals only, not all flights
Cancelled
0.59%
National rate is 1.81%
Whole route
77.2%
Every carrier on PHX to DEN, 8,920 flights
These figures cover 2,370 flights between July 2025 and June 2026. The median arrival is 8 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 PHX to DEN
United flew 2,370 of the 8,920 flights on PHX to DEN, about 27% of it. Its 83.5% on time is 6 points better than the route as a whole, which runs 77.2%. Ranked by on-time rate it is first of six carriers on the route, where the range runs from United at 83.5% to SkyWest at 66.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. Frontier Airlines arrives on time 80.0% of the time; Southwest Airlines manages 72.8%. Sample sizes sit next to every figure, because a two-point gap across 3,942 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 2,370 | 83.5% | 75 min | 0.59% | B+ |
| Envoy Airthin sample | 189 | 81.8% | 53 min | 0.53% | B+ |
| Frontier Airlines | 1,427 | 80.0% | 88 min | 0.63% | B+ |
| American Airlines | 974 | 74.8% | 66 min | 0.62% | C+ |
| Southwest Airlines | 3,942 | 72.8% | 56 min | 0.81% | C+ |
| SkyWest Airlinesthin sample | 18 | 66.7% | 98 min | 0.00% | C+ |
Frontier leads Southwest by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
United flight numbers on PHX to DEN
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 16 points, against 7 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am415 flights93.0%
- 8am–11am375 flights89.0%
- 11am–2pm531 flights84.2%
- 2pm–5pm637 flights77.4%
- 5pm–8pm385 flights78.3%
- 8pm–5am27 flights—
Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.0% of the time, against 77.4% for the afternoon window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 2pm–5pm window is the busiest, with 637 flights scheduled in it.
Across the year
United on PHX to DEN through the year
July is the worst month at 68.7% on time, 23 points below January, the best at 91.8%. 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 250 flights.
Across the week, Tuesday is the strongest day at 86.6% on time and Sunday the weakest at 81.8%. 5 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 43% of the 29,000 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.
- 43%Late-arriving aircraft
- 35%National Airspace System
- 20%Carrier
- 3%Extreme weather
43% 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 29,000 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 28,830 reported delay minutes.
35% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 10,000 minutes out of 29,000, against a national NAS share of 21%.
Cancellations are rare at 0.59%, 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
6.6% 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 a little over an hour, which a normal layover absorbs.
The 602 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 80.5% on time across 2,369 flights, 3 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 3 points of difference.
The sample behind these figures is 2,370 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 United on PHX to DEN
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 91.8% on time and July 68.7%, a swing of 23 points. If the dates move at all, move them out of July before you think about anything else. 2,347 completed flights over 12 months sit behind that.
Related
Where to go next
- PHX to DEN, every carrier
- United on DEN to PHX, the return leg
- Envoy Air on PHX to DEN81.8%
- Frontier Airlines on PHX to DEN80.0%
- American Airlines on PHX to DEN74.8%
- Southwest Airlines on PHX to DEN72.8%
- United Airlines network-wide record
- Phoenix Sky Harbor International (PHX) delay statistics
- Denver International (DEN) 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.