Route reliability record
PIT→DEN
Pittsburgh to Denver
- Flights
- 1,698
- Period
- July 2025 to June 2026
- Distance
- 1,290 mi
- Carriers
- 3
This route lands a B+, 4 points better than the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 1,698 PIT to DEN flights, of which United Airlines flew 883 at 86.8% on time.
Best time to fly PIT to DEN: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 94.1% of the time and Wednesday flights 85.0%, against 81.6% for the route overall.
Set against the rest of the country, this route's record is 4 points better than the US average of 77.6%. That gap is worth roughly 40 fewer late arrivals for every thousand flights.
Key figures
On time
81.6%
Arrivals under 15 minutes late, of 1,682 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.71%
National rate is 1.81%
Best carrier
United
86.8% on time across 883 flights
These figures cover 1,698 flights between July 2025 and June 2026. The median arrival is 7 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
Which airline is most reliable on PIT to DEN
The choice of carrier is not cosmetic here. United Airlines arrives on time 86.8% of the time; Southwest Airlines manages 75.9%. Sample sizes sit next to every figure, because a two-point gap across 766 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 883 | 86.8% | 61 min | 0.68% | A+ |
| Frontier Airlinesthin sample | 49 | 77.6% | 105 min | 0.00% | B+ |
| Southwest Airlines | 766 | 75.9% | 61 min | 0.78% | B+ |
United leads Southwest by 11 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.
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 | 86.2% | 86.8% | 0.68% | 8am–11am, Sun | UA 1765 08:30 |
| 2. PIT → DENPittsburgh to Denver | Southwest Airlines | 75.3% | 75.9% | 0.78% | 8am–11am, Wed | — |
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 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am270 flights94.1%
- 8am–11am556 flights91.8%
- 11am–2pm93 flights81.5%
- 2pm–5pm421 flights77.6%
- 5pm–8pm301 flights59.5%
- 8pm–5am57 flights69.6%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 59.5% on time, against 94.1% 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 556 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 25 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.
June is the worst month at 69.1% on time, 25 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. July was the busiest month here, with 185 flights.
Across the week, Wednesday is the strongest day at 85.0% on time and Thursday the weakest at 77.3%. 8 points is a smaller lever than departure hour, but it is free.
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 19,000 reported delay minutes.
- 36%National Airspace System
- 34%Late-arriving aircraft
- 27%Carrier
- 2%Extreme weather
34% 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 19,000 reported delay minutes here, that single category outweighs weather by 14 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 19,303 reported delay minutes.
36% 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 7,026 minutes out of 19,000, against a national NAS share of 21%.
Cancellations are rare at 0.71%, 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 actually costs
5.8% 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 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. 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 72.7% on time across 1,696 flights, 9 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 9 points of difference.
The sample behind these figures is 1,698 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 June 69.1%, a swing of 25 points. If the dates move at all, move them out of June before you think about anything else. 1,682 completed flights over 12 months sit behind that.
Common questions
PIT to DEN questions
How often is PIT to DEN delayed?
Roughly 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 18.4% of the 1,698 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on PIT to DEN?
United Airlines leads at 86.8% on time across 883 flights. Southwest Airlines is at the other end on 75.9%, a gap of 11 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 94.1% on time. The 5pm–8pm window is the weakest at 59.5%, 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 June delays on PIT to DEN?
June is the weakest month at 69.1% on time, compared with 93.7% in November. Across the year that is 25 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 DEN86.8%
- Southwest Airlines on PIT to DEN75.9%
- PIT to ORD, a related route78.6%
- PHX to DEN, a related route77.2%
- PIT to LGA, a related route80.9%
- United Airlines on-time record86.8%
- Frontier Airlines on-time record77.6%
- Southwest Airlines on-time record75.9%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.