Carrier route record
UAPHL→DEN
United Airlines · Philadelphia to Denver
- Flights
- 953
- Period
- July 2025 to June 2026
- Share of route
- 32%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.
United on PHL 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 an hour and a half on average. That is a workable record, not a spotless one. That rests on 953 flights. The strongest carrier on the route with a full sample, American Airlines, flew 877 at 73.3% on time.
Set against the rest of the country, United's PHL to DEN record is 6 points better than the US average of 77.6%. That gap is worth roughly 63 fewer late arrivals for every thousand flights.
Key figures
On time
83.9%
Arrivals under 15 minutes late, of 940 completed flights
Avg delay
92 min
Across delayed arrivals only, not all flights
Cancelled
0.84%
National rate is 1.81%
Whole route
74.9%
Every carrier on PHL to DEN, 3,005 flights
These figures cover 953 flights between July 2025 and June 2026. The median arrival is 9 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 PHL to DEN
United flew 953 of the 3,005 flights on PHL to DEN, about 32% of it. Its 83.9% on time is 9 points better than the route as a whole, which runs 74.9%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from United at 83.9% to Frontier at 68.4%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines (this page) | 953 | 83.9% | 92 min | 0.84% | B+ |
| American Airlines | 877 | 73.3% | 66 min | 1.60% | C |
| Southwest Airlines | 879 | 69.0% | 57 min | 0.80% | C+ |
| Frontier Airlinesthin sample | 296 | 68.4% | 112 min | 1.69% | C |
No carrier stands out. American tops the table at 73.3%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
United flight numbers on PHL 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 13 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am4 flights—
- 8am–11am583 flights88.7%
- 11am–2pm—
- 2pm–5pm364 flights76.0%
- 5pm–8pm—
- 8pm–5am2 flights—
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 88.7% of the time, against 76.0% for the afternoon window. That is 13 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 583 flights scheduled in it.
Across the year
United on PHL to DEN through the year
December is the weak month at 72.7% on time, against 92.2% in November. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. August was the busiest month here, with 93 flights.
Across the week, Saturday is the strongest day at 87.6% on time and Thursday the weakest at 76.7%. 11 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. Carrier accounts for 51% of the 14,000 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.
- 51%Carrier
- 24%National Airspace System
- 20%Late-arriving aircraft
- 6%Extreme weather
The largest share of delay minutes, 51%, 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 7,055 of the 14,000 delay minutes reported here. The split is drawn from 13,893 reported delay minutes.
Cancellations are rare at 0.84%, 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
5.7% 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 an hour and a half, which a normal layover absorbs.
At 1,558 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 79.9% on time across 952 flights, 4 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 4 points of difference.
One caution: this is a thin sample. 953 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 PHL to DEN
Put together: treat all of this as provisional. 953 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 83.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 940 completed flights over 12 months sit behind that.
Related
Where to go next
- PHL to DEN, every carrier
- United on DEN to PHL, the return leg
- American Airlines on PHL to DEN73.3%
- Southwest Airlines on PHL to DEN69.0%
- Frontier Airlines on PHL to DEN68.4%
- United Airlines network-wide record
- Philadelphia International (PHL) delay statistics
- Denver International (DEN) delay statistics
- The best time of day to fly, according to 7.04 million flight records
- Worst months to fly in the US, ranked by the data
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.