Route profile
PHL→DEN
Flight reliability, delays and best times to fly from Philadelphia to Denver, 1,558 miles.
Right now
Aviation weather is not currently a factor.
Aviation weather is not currently a factor.
Route reliability
July 2023 – July 2026
Better than 36% of comparable major US routes (4,598 compared)
Calculated from 9,299 flights. How this is calculated · What counts as on time
PHL → DEN arrives on time 76.8% of the time; the return trip, DEN → PHL, arrives on time 73.1% of the time, a 3.7-point gap between the two directions of the same city pair.
PHL → DEN spends 29.8 minutes on the ground on a 1,558-mile trip: 19.3 minutes from pushback to wheels-up at PHL and 10.5 minutes from touchdown to gate at DEN.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
What stands out
Every day of the week performs about the same on this route, steadier than 96% of 4,467 comparable routes.
79.3% on time on the best day (Wednesday) against 75.3% on the worst (Friday).
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Ranked against every other route with the same kind of figure and at least 4,467 in the comparison.
What sets this route apart
Where PHL to DEN differs most from similar routes by hour, weekday, month and airline, July 2023 – July 2026.
PHL to DEN struggles most at 5 PM: 50.9% of its flights scheduled then arrive on time, 19.1 points behind the 70.0% on routes of similar length at the same hour. Against all other routes the gap is 18.9 points.
PHL to DEN is at its best against routes of similar length for flights scheduled at 3 PM: 79.3% arrive on time, 7.5 points ahead of the 71.8% those routes manage at that hour. Against all other routes the gap is 6.6 points.
In December, PHL to DEN runs 5.3 points below routes of similar length, 74.1% on time to 79.4%. Against all other routes the gap is 4.7 points.
March is kinder to PHL to DEN than to routes of similar length: 82.8% on time against 78.4%, 4.4 points better. Against all other routes the gap is 4.9 points.
United Airlines does better on PHL to DEN than on its routes of similar length: 85.9% on time here, 80.6% there, 5.3 points apart. Against all other routes the gap is 6 points.
PHL to DEN against comparable routes
July 2023 – July 2026| Measure | This route | Compared with | Them | Gap | Flights behind it |
|---|---|---|---|---|---|
| Hour: 5 PM departures | 50.9% | routes of similar length | 70.0% | −19.1 pts | 352 here, 107,394 there |
| Hour: 3 PM departures | 79.3% | routes of similar length | 71.8% | +7.5 pts | 1,170 here, 83,993 there |
| Month: December | 74.1% | routes of similar length | 79.4% | −5.3 pts | 673 here, 129,417 there |
| Month: March | 82.8% | routes of similar length | 78.4% | +4.4 pts | 638 here, 131,715 there |
| Airline: United Airlines | 85.9% | routes of similar length | 80.6% | +5.3 pts | 3,010 here, 369,317 there |
Each comparison pools the flights of other routes, with this route’s own left out. Similar length means within 15% of this route’s 1,558 miles, with at least 5 such routes. A bucket is set against the most comparable group that has enough flights: similar length, then the same origin (at least 3 routes), then all other routes. Hours, weekdays and months appear only where both sides have 120 completed flights, and airlines where both have 600. The gap must be at least 2 points and 2 standard errors, and only the largest gap each way is kept per measure. These are differences in the flights counted, not causes.
Why PHL → DEN flights are cancelled
July 2023 – July 2026
PHL → DEN cancelled 124 of 9,299 scheduled flights — about 1 in every 75. The reason filed most often was extreme weather, 63.7% of the cancellations coded on this route — about 1 in every 118 scheduled flights.
Share of cancellations
Of 124 cancelled departures carrying a reason code.
What each reason means
Conditions the carrier judged severe enough to stop the flight: a blizzard, a hurricane, a line of thunderstorms.
79 cancellations, 63.7% of the total.
Crew, maintenance, aircraft cleaning, baggage or fueling: what BTS counts as within the carrier’s own control.
37 cancellations, 29.8% of the total.
Airport capacity, air traffic control flow programs, heavy traffic and ordinary bad weather. A system decision, not the airline’s.
8 cancellations, 6.5% of the total.
A terminal evacuation, a security breach, screening equipment failure, or screening queues over 29 minutes.
0 cancellations, 0.0% of the total.
Reason codes are the operating airline’s own filing with US DOT, not an independent finding of fault. Ordinary bad weather is filed under air traffic, so weather’s full share is larger than its bar.
124 coded cancellations were recorded on PHL → DEN; the section appears from 50.
When it goes wrong
July 2023 – July 2026
49 min late
against a median of 6 min early
Percentiles over 9,299 operations; cancelled and diverted flights are counted separately.
Will your connection be tight enough?
Layovers at DEN after arriving from PHL.
| Connection time | Chance of missing | Reads as |
|---|---|---|
| 30 min | 38% | Likely to miss |
| 45 min | 22% | High risk |
| 60 min | 15% | Some risk |
| 90 min | 8.0% | Some risk |
| 120 min | 5.2% | Some risk |
This is one leg of a connection. Gate changes and the next flight's own schedule matter too. And a connection can fail before delay is even the question — this route cancels 1.33% of the time and diverts 0.35% of the time, which a late arrival never shows up in.
Chance of missing is the share of 9,142 arrivals on this route that landed later than the connection time less 30 minutes to reach the next gate.
The worst tenth of arrivals on this route land at least 49 minutes late (90th-percentile gate arrival delay), over 9,299 operations.
Any other layover length: connection checker.
Best time to fly
PHL → DEN flights departing 5–9 AM arrived on time 87.4% of the time, against 62.9% for 6–9 PM departures, a gap of 24.5 percentage points.
By departure window
By departure hour
- 12 AM to 4 AM: too few flights to score
- 5 AM: 90.8% on time from 513 flights
- 6 AM: 81.4% on time from 516 flights
- 7 AM: 89.7% on time from 512 flights
- 8 AM: 87.4% on time from 1,284 flights
- 9 AM: 83.5% on time from 591 flights
- 10 AM: 86.3% on time from 895 flights
- 11 AM: 78.1% on time from 424 flights
- 12 PM: 72.6% on time from 200 flights
- 1 PM: 66.1% on time from 377 flights
- 2 PM: 74.6% on time from 131 flights
- 3 PM: 79.3% on time from 1,193 flights
- 4 PM: 61.7% on time from 289 flights
- 5 PM: 50.9% on time from 363 flights
- 6 PM: 57.9% on time from 451 flights
- 7 PM: 63.1% on time from 698 flights
- 8 PM: 65.8% on time from 768 flights
- 9 PM to 11 PM: too few flights to score
Departure windows with fewer than 120 flights are not scored.
Why PHL → DEN runs late
July 2023 – July 2026
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for PHL → DEN. Only delays of 15 minutes or more are attributed. What the five causes mean
Airlines on this route
Carriers with at least 200 flights, by the airline that operated each one.
| Carrier | Flights | On time | Cancelled | Median delay | Severe |
|---|---|---|---|---|---|
| United Airlines | 3,053 | 85.9% | 0.85% | -11 min | 5.4% |
| American Airlines | 2,631 | 73.5% | 1.90% | -5 min | 10.1% |
| Southwest Airlines | 2,447 | 73.7% | 0.69% | -2 min | 6.8% |
| Frontier Airlines | 1,168 | 67.2% | 2.65% | -2 min | 14.3% |
United Airlines flew 32.8% of the 9,299 flights listed. Frontier Airlines cancelled 2.65% of its flights here against 0.69% for Southwest Airlines.
United Airlines arrived on time 18.7 percentage points more often than Frontier Airlines on this route.
Weekly and seasonal patterns
By day of week
Wednesday is historically the most reliable day and Friday the least, a gap of 4.0 percentage points.
By month
- Jan: 76.5%
- Feb: 80.4%
- Mar: 82.8%
- Apr: 79.2%
- May: 73.9%
- Jun: 69.5%
- Jul: 66.4%
- Aug: 76.7%
- Sep: 83.0%
- Oct: 85.5%
- Nov: 83.7%
- Dec: 74.1%
July is historically the weakest month and October the strongest, a spread of 19.1 percentage points.
Reliability over time
July 2023 – July 2026
- July 2023: 58.7% from 286 flights
- August 2023: 81.3% from 294 flights
- September 2023: 80.3% from 275 flights
- October 2023: 81.3% from 275 flights
- November 2023: 85.8% from 226 flights
- December 2023: 87.7% from 219 flights
- January 2024: 76.2% from 198 flights
- February 2024: 89.1% from 157 flights
- March 2024: 83.8% from 199 flights
- April 2024: 83.3% from 258 flights
- May 2024: 73.6% from 285 flights
- June 2024: 72.8% from 296 flights
- July 2024: 71.2% from 309 flights
- August 2024: 72.2% from 296 flights
- September 2024: 84.7% from 281 flights
- October 2024: 94.8% from 250 flights
- November 2024: 79.2% from 219 flights
- December 2024: 80.2% from 222 flights
- January 2025: 80.0% from 198 flights
- February 2025: 72.3% from 182 flights
- March 2025: 87.9% from 243 flights
- April 2025: 72.7% from 216 flights
- May 2025: 71.5% from 259 flights
- June 2025: 71.4% from 306 flights
- July 2025: 68.8% from 317 flights
- August 2025: 76.6% from 309 flights
- September 2025: 84.0% from 283 flights
- October 2025: 80.6% from 248 flights
- November 2025: 85.7% from 239 flights
- December 2025: 55.6% from 236 flights
- January 2026: 72.9% from 177 flights
- February 2026: 80.8% from 173 flights
- March 2026: 75.7% from 206 flights
- April 2026: 80.8% from 225 flights
- May 2026: 76.4% from 276 flights
- June 2026: 64.7% from 316 flights
- July 2026: 66.2% from 345 flights
Over the most recent 12 months (2025-08 to 2026-07), on-time arrivals averaged 74.5% against 77.7% in the 12 months before — declining by 3.2 percentage points.
Data and methodology
Calculated by FlyerIntel from 9,299 PHL → DEN flight records from the US DOT Bureau of Transportation Statistics, covering July 2023 – July 2026. Late means 15 or more minutes past scheduled arrival; cancelled and diverted flights are left out of on-time rates.
Full methodology · Data sources · Report a problem
Related research: How Long a Layover Needs to Be · Two Airlines on One Route · Best Time of Day to Fly From Major US Airports
Analysis last recomputed