Route reliability record
DEN→PIT
Denver to Pittsburgh
- Flights
- 1,696
- Period
- July 2025 to June 2026
- Distance
- 1,290 mi
- Carriers
- 3
This route sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 1,696 DEN to PIT flights, of which United Airlines flew 882 at 79.6% on time.
Best time to fly DEN to PIT: a 8am–11am departure, ideally on a Sunday. Flights in that window arrived on time 80.5% of the time and Sunday flights 80.0%, against 72.7% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 5 points behind the country as a whole. Across a thousand flights that is about 49 extra late arrivals.
Key figures
On time
72.7%
Arrivals under 15 minutes late, of 1,686 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.53%
National rate is 1.81%
Best carrier
United
79.6% on time across 882 flights
These figures cover 1,696 flights between July 2025 and June 2026. Beyond the headline rate, 8.6% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on DEN to PIT
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.6% of the time; Southwest Airlines manages 63.7%. Sample sizes sit next to every figure, because a two-point gap across 765 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Frontier Airlinesthin sample | 49 | 89.8% | 119 min | 0.00% | A+ |
| United Airlines | 882 | 79.6% | 59 min | 0.57% | B+ |
| Southwest Airlines | 765 | 63.7% | 54 min | 0.52% | D+ |
The spread between United and Southwest is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 more arrivals inside the on-time window.
Best ways to make this trip
The most reliable ways to fly Denver to Pittsburgh
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. DEN → PITDenver to Pittsburgh | United Airlines | 79.1% | 79.6% | 0.57% | 8am–11am, Tue | — |
| 2. DEN → PITDenver to Pittsburgh | Southwest Airlines | 63.4% | 63.7% | 0.52% | 8am–11am, Sun | — |
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 26 points, against 16 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am19 flights—
- 8am–11am634 flights80.5%
- 11am–2pm132 flights78.8%
- 2pm–5pm273 flights69.6%
- 5pm–8pm593 flights66.0%
- 8pm–5am45 flights54.5%
Scale runs 45% to 85%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 54.5% on time, against 80.5% for the 8am–11am 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 634 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 34 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.
July is the worst month at 56.9% on time, 34 points below February, the best at 91.3%. 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, Sunday is the strongest day at 80.0% on time and Thursday the weakest at 65.5%. 15 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 54% of the 26,000 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.
- 54%Late-arriving aircraft
- 30%Carrier
- 15%National Airspace System
- 1%Extreme weather
54% 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 26,000 reported delay minutes here, that single category outweighs weather by 41 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 26,182 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 80.5% on time here.
Cancellations are rare at 0.53%, 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
8.6% 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 81.6% on time across 1,698 flights, 9 points above 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 1,696 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 PIT 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. February runs 91.3% on time and July 56.9%, a swing of 34 points. If the dates move at all, move them out of July before you think about anything else. 1,686 completed flights over 12 months sit behind that.
Common questions
DEN to PIT questions
How often is DEN to PIT delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 27.3% of the 1,696 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on DEN to PIT?
United Airlines leads at 79.6% on time across 882 flights. Southwest Airlines is at the other end on 63.7%, a gap of 16 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 DEN to PIT?
The 8am–11am departure window is the strongest at 80.5% on time. The 8pm–5am window is the weakest at 54.5%, 26 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 July delays on DEN to PIT?
July is the weakest month at 56.9% on time, compared with 91.3% in February. Across the year that is 34 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
- PIT to DEN — the return legseparate record
- Denver International (DEN) delay statistics
- Pittsburgh International (PIT) delay statistics
- United Airlines on DEN to PIT79.6%
- Southwest Airlines on DEN to PIT63.7%
- DEN to PHX, a related route75.7%
- ORD to PIT, a related route74.9%
- DEN to SLC, a related route77.5%
- Frontier Airlines on-time record89.8%
- United Airlines on-time record79.6%
- Southwest Airlines on-time record63.7%
- Same route, different airline: where the carrier you pick matters most
- Why the first flight of the morning is statistically safest
Direction matters. DEN to PIT and PIT to DEN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed DEN to PIT’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.