Route on-time record

PHL to DEN: most on-time flights and the best time to fly

Philadelphia (Philadelphia International Airport) to Denver (Denver International Airport). 2,995 nonstop flights in Jun 2025 to May 2026, 76% arrived within 15 minutes and 1.3% were cancelled. The most reliable flight number was United 1537 at 10:00 AM.

Flying on a specific date? We’ll adjust for the month, the weekday and the forecast.

PHL → DEN

Philadelphia to Denver: 2,995 nonstop flights a year

On time (12 months)

76%

Cancelled

1.3%

avg delay 20 min

Best time to leave

Before 9 AM

85% on time vs 60% 6 to 9 PM

Most reliable airline

United

83% chance on time

Check PHL to DEN fares

Fares open on our travel partner (Aviasales). Pick the flight number you chose here.

Most reliable nonstop flights

Ranked by the chance the flight operates and arrives within 15 minutes of schedule, from Jun 2025 to May 2026 records.

#1 · United 1537
10:00 AM → 12:01 PM4h 01m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as United 2633; its record covers all of them.
90%
chance on time
On time (history)
97%
Cancelled
0.0%
Avg arrival delay
5 min
- Arrived on time 97% of the time (29 flights, Jun 2025 to May 2026).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
- Short track record (29 flights), so its score leans on the airline's record at this hour.
Limited track record · 29 flights
Find United 1537 fares Opens this date on Aviasales
#2 · United 644
8:00 AM → 10:01 AM4h 01m nonstop
Local times, typical schedule. Last flown 2026-05-31. Same departure also flew as United 2478, 2383; its record covers all of them.
88%
chance on time
On time (history)
89%
Cancelled
1.4%
Avg arrival delay
9 min
- Arrived on time 89% of the time (358 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; 6 to 9 PM: 60%).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Strong track record · 358 flights
Find United 644 fares Opens this date on Aviasales
#3 · Southwest 2557
5:40 AM → 7:45 AM4h 05m nonstop
Local times, typical schedule. Last flown 2026-05-31.
82%
chance on time
On time (history)
87%
Cancelled
0.0%
Avg arrival delay
5 min
- Arrived on time 87% of the time (55 flights, Jun 2025 to May 2026).
- Never cancelled in 55 scheduled flights.
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; 6 to 9 PM: 60%).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Limited track record · 55 flights
Find Southwest 2557 fares Opens this date on Aviasales
#4 · American 3312
8:46 AM → 11:08 AM4h 22m nonstop
Local times, typical schedule. Last flown 2026-05-31.
82%
chance on time
On time (history)
80%
Cancelled
0.0%
Avg arrival delay
23 min
- Arrived on time 80% of the time (10 flights, Jun 2025 to May 2026).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; 6 to 9 PM: 60%).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
- 74% of its delay minutes came from the plane arriving late from an earlier flight.
Limited track record · 10 flights
Find American 3312 fares Opens this date on Aviasales
#5 · American 3256
9:13 AM → 11:35 AM4h 22m nonstop
Local times, typical schedule. Last flown 2026-05-20.
82%
chance on time
On time (history)
84%
Cancelled
0.0%
Avg arrival delay
7 min
- Arrived on time 84% of the time (44 flights, Jun 2025 to May 2026).
- Never cancelled in 44 scheduled flights.
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
- Short track record (44 flights), so its score leans on the airline's record at this hour.
Limited track record · 44 flights
Find American 3256 fares Opens this date on Aviasales
#6 · American 1534
10:58 AM → 1:19 PM4h 21m nonstop
Local times, typical schedule. Last flown 2026-04-06.
81%
chance on time
On time (history)
85%
Cancelled
1.9%
Avg arrival delay
17 min
- Arrived on time 85% of the time (53 flights, Jun 2025 to May 2026).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
- Short track record (53 flights), so its score leans on the airline's record at this hour.
Limited track record · 53 flights
Find American 1534 fares Opens this date on Aviasales
#7 · United 2411
3:34 PM → 5:55 PM4h 21m nonstop
Local times, typical schedule. Last flown 2026-05-20. Same departure also flew as United 2093; its record covers all of them.
81%
chance on time
On time (history)
80%
Cancelled
0.0%
Avg arrival delay
18 min
- Arrived on time 80% of the time (66 flights, Jun 2025 to May 2026).
- Never cancelled in 66 scheduled flights.
- Departs inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Moderate track record · 66 flights
Find United 2411 fares Opens this date on Aviasales
#8 · Southwest 4170
5:20 AM → 7:30 AM4h 10m nonstop
Local times, typical schedule. Last flown 2026-04-06.
79%
chance on time
On time (history)
84%
Cancelled
3.0%
Avg arrival delay
5 min
- Arrived on time 84% of the time (32 flights, Jun 2025 to May 2026).
- Cancelled 3.0% of the time (1 of 33).
- Leaves in this route's most on-time window (Before 9 AM: 85% on time; 6 to 9 PM: 60%).
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
Limited track record · 32 flights
Find Southwest 4170 fares Opens this date on Aviasales
#9 · United 2433
3:40 PM → 6:01 PM4h 21m nonstop
Local times, typical schedule. Last flown 2026-04-29.
79%
chance on time
On time (history)
78%
Cancelled
0.0%
Avg arrival delay
11 min
- Arrived on time 78% of the time (32 flights, Jun 2025 to May 2026).
- Never cancelled in 32 scheduled flights.
- Departs inside PHL's trouble window: 72% of its 95 ground stops and delay programs started between 2 PM and 8 PM.
- Lands inside DEN's trouble window: 79% of its 174 ground stops and delay programs started between 2 PM and 8 PM.
Limited track record · 32 flights
Find United 2433 fares Opens this date on Aviasales
#10 · American 3262
11:09 AM → 1:31 PM4h 22m nonstop
Local times, typical schedule. Last flown 2026-05-18.
78%
chance on time
On time (history)
87%
Cancelled
0.0%
Avg arrival delay
6 min
- Arrived on time 87% of the time (30 flights, Jun 2025 to May 2026).
- Never cancelled in 30 scheduled flights.
- Departs outside PHL's trouble window (2 PM to 8 PM, when 72% of its 95 ground stops and delay programs started).
- Short track record (30 flights), so its score leans on the airline's record at this hour.
Limited track record · 30 flights
Find American 3262 fares Opens this date on Aviasales

Airlines on this route

Season-adjusted chance of operating and arriving on time.

United Airlines83%
961 flights · 84% on time as flown · 1.1% cancel
American Airlines73%
852 flights · 75% on time as flown · 1.7% cancel
Southwest Airlines69%
878 flights · 70% on time as flown · 1.0% cancel
Frontier Airlines69%
304 flights · 68% on time as flown · 1.5% cancel

On time by departure time

All airlines, scheduled local departure, Jun 2025 to May 2026.

Before 9 AM85%
1,031 flights · avg delay 11 min
9 AM to noon83%
559 flights · avg delay 14 min
Noon to 3 PM68%
213 flights · avg delay 20 min
3 to 6 PM69%
617 flights · avg delay 30 min
6 to 9 PM60%
542 flights · avg delay 31 min

Best day: Wednesday (81%). Worst: Sunday (76%).

On time by month

All airlines, Jun 2023 to May 2026. Several years per month, so one stormy season doesn't define a month. Travel-month estimates use this seasonal pattern.

What delays this route

Airline (crew, maintenance, boarding)38%
Late-arriving aircraft36%
Air traffic control and airport volume22%
Severe weather4%

Share of delay minutes by the cause airlines report to the US DOT.

Historical odds, not a guarantee. Built from the US DOT Bureau of Transportation Statistics on-time reports (Jun 2025 to May 2026), FAA ground stop and delay program advisories, and 20 years of airport weather observations. Covers US airlines that report to the DOT; schedules are flights operated recently, so confirm times when you book. ATIS Alerts is not affiliated with any airline. Fares are what Aviasales travelers saw in recent searches (USD, one way, 1 adult), not live quotes; the partner site shows the current price. Fare links go to our travel partner and may earn us a commission at no cost to you. Affiliate disclosure

PHL to DEN questions

What time of day is best to fly PHL to DEN?: Before 9 AM: 85% of flights arrived on time, against 60% for departures 6 to 9 PM. Later flights inherit delays from earlier ones, so the first departures of the day usually run best.
Which airline is most on time from PHL to DEN?: United, with a season-adjusted 83% chance of operating and arriving on time over 961 flights. The adjustment compares each airline with what the route did in the months it flew, so a carrier that skipped a stormy month gets no free credit.
What is the worst month for delays on PHL to DEN?: July (66% on time); the best was October (85%), averaged over Jun 2023 to May 2026.
Is this a prediction for my flight?: No. These are historical odds from the US DOT on-time reports, FAA advisories and airport weather records. Check your flight status and the FAA delay board on the day you fly.

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