Route reliability record
PIT→DEN
Pittsburgh to Denver
- Flights
- 1,623
- Period
- September 2025 to August 2026
- Distance
- 1,290 mi
- Carriers
- 3
This route lands a B+, 4 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 1,623 PIT to DEN flights, of which United Airlines flew 820 at 86.4% on time.
Best time to fly PIT to DEN: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 93.1% of the time and Wednesday flights 84.3%, against 80.8% for the route overall.
The US average over the same twelve months is 77.3%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
80.8%
Arrivals under 15 minutes late, of 1,609 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.89%
Best carrier
United
86.4% on time across 820 flights
These figures cover 1,623 flights between September 2025 and August 2026. The median arrival is 6 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.
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Carrier by carrier
Which airline is most reliable on PIT to DEN
The choice of carrier is not cosmetic here. United Airlines arrives on time 86.4% of the time; Southwest Airlines manages 74.6%. Sample sizes sit next to every figure, because a two-point gap across 768 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 820 | 86.4% | 78 min | 0.73% | A+ |
| Frontier Airlinesthin sample | 35 | 85.7% | 67 min | 0.00% | A+ |
| Southwest Airlines | 768 | 74.6% | 57 min | 0.78% | C+ |
United leads Southwest by 12 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on PIT to DEN
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Pittsburgh to Denver
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. PIT → DENPittsburgh to Denver | United Airlines | 85.8% | 86.4% | 0.73% | 8am–11am, Wed | UA 1765 08:30 |
| 2. PIT → DENPittsburgh to Denver | Southwest Airlines | 74.0% | 74.6% | 0.78% | 5am–8am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 35 points, against 12 points between the best and worst carrier.
- 5am–8am275 flights93.1%
- 8am–11am483 flights91.6%
- 11am–2pm92 flights76.9%
- 2pm–5pm412 flights78.9%
- 5pm–8pm304 flights58.1%
- 8pm–5am57 flights69.6%
Scale runs 50% to 100%.
The 5pm–8pm window is where this operation falls apart: 58.1% on time, against 93.1% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 483 flights scheduled in it.
Explore
Filter PIT to DEN by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On PIT to DEN, the best departure window is 5am–8am at 93.1% on time and the worst is 5pm–8pm at 58.1%, a wide gap of 35.0 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am93.1%
- 8–11am91.6%
- 11am–2pm76.9%
- 2–5pm78.9%
- 5–8pm58.1%
- 8pm–5am69.6%
best all US flightsScale 50% to 100%.
Across the year
When delays peak on this route
This route's year swings by 29 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 65.2% on time, 29 points below November, the best at 93.7%. 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 178 flights.
Across the week, Wednesday is the strongest day at 84.3% on time and Thursday the weakest at 76.6%, a spread of 8 points.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 20,000 reported delay minutes.
- 35%National Airspace System
- 29%Late-arriving aircraft
- 29%Carrier
- 7%Extreme weather
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 6,966 minutes out of 20,000, against a national NAS share of 21%. The split is drawn from 19,995 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 93.1% on time here.
Cancellations are rare at 0.74%, below the national 1.89% 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 actually costs
6.1% of arrivals land an hour or more late, close to the national 8.3%, so 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 1,290 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.
The return leg is a different operation and performs like one: it runs 74.1% on time across 1,622 flights, 7 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 7 points of difference.
The sample behind these figures is 1,623 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.
Work out the risk of missing a connection in DEN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 93.7% on time and August 65.2%, a swing of 29 points. If the dates move at all, move them out of August before you think about anything else. 1,609 completed flights over 12 months sit behind that.
Common questions
PIT to DEN questions
How often is PIT to DEN delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 19.2% of the 1,623 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on PIT to DEN?
United Airlines leads at 86.4% on time across 820 flights. Southwest Airlines is at the other end on 74.6%, a gap of 12 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on PIT to DEN?
The 5am–8am departure window is the strongest at 93.1% on time. The 5pm–8pm window is the weakest at 58.1%, 35 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are August delays on PIT to DEN?
August is the weakest month at 65.2% on time, compared with 93.7% in November. Across the year that is 29 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DEN to PIT — the return legseparate record
- Pittsburgh International (PIT) delay statistics
- Denver International (DEN) delay statistics
- United Airlines on PIT to DEN86.4%
- Southwest Airlines on PIT to DEN74.6%
- PIT to ORD, a related route77.1%
- PHX to DEN, a related route76.7%
- PIT to LGA, a related route79.9%
- United Airlines on-time record86.4%
- Frontier Airlines on-time record85.7%
- Southwest Airlines on-time record74.6%
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.05 million flight records
Direction matters. PIT to DEN and DEN to PIT are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.