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DelayAtlas

Carrier route record

UADENPIT

United Airlines · Denver to Pittsburgh

Flights
882
Period
July 2025 to June 2026
Share of route
52%
Carriers
3
B+GRADE

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.

United on DEN to PIT lands a B+, 2 points better than the national rate of 77.6%. About 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 882 flights, with a median arrival 6 minutes early.

The US average over the same twelve months is 77.6%, so there is little to separate United on DEN to PIT from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

Key figures

On time

79.6%

Arrivals under 15 minutes late, of 876 completed flights

Avg delay

59 min

Across delayed arrivals only, not all flights

Cancelled

0.57%

National rate is 1.81%

Whole route

72.7%

Every carrier on DEN to PIT, 1,696 flights

These figures cover 882 flights between July 2025 and June 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.

Carrier by carrier

United against every carrier on DEN to PIT

United flew 882 of the 1,696 flights on DEN to PIT, most of the route. Its 79.6% on time is 7 points better than the route as a whole, which runs 72.7%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from Frontier at 89.8% to Southwest at 63.7%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

On-time performance by carrier on DEN to PIT
AirlineFlightsOn timeAvg delayCancelledGrade
Frontier Airlinesthin sample4989.8%119 min0.00%A+
United Airlines (this page)88279.6%59 min0.57%B+
Southwest Airlines76563.7%54 min0.52%D+

Departure window

When United runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 882 flights.

  • 5am–8am
  • 8am–11am365 flights83.5%
  • 11am–2pm
  • 2pm–5pm148 flights81.8%
  • 5pm–8pm364 flights74.9%
  • 8pm–5am5 flights

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 83.5% of the time, against 74.9% for the evening window. That is 9 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8am–11am window is the busiest, with 365 flights scheduled in it.

Across the year

United on DEN to PIT through the year

On-time rate by calendar month82J93F69M87A84M75J62J66A80S91O85N89D
Darker means more delays. Figures are on-time percentages.February best, July worst

July is the worst month at 61.5% on time, 31 points below February, the best at 92.9%. 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 93 flights.

Across the week, Tuesday is the strongest day at 85.2% on time and Thursday the weakest at 72.4%. 13 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week74.6Mon85.2Tue77.6Wed72.4Thu81.6Fri82.3Sat83.2Sun
Monday: 74.6 percent on time. Tuesday: 85.2 percent on time. Wednesday: 77.6 percent on time. Thursday: 72.4 percent on time. Friday: 81.6 percent on time. Saturday: 82.3 percent on time. Sunday: 83.2 percent on time

Delay causes

Why United runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 54% of the 11,000 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.

  • Late-arriving aircraft
    54%
  • Carrier
    25%
  • National Airspace System
    19%
  • Extreme weather
    2%

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 11,000 reported delay minutes here, that single category outweighs weather by 22 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 10,598 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 83.5% on time here.

Cancellations are rare at 0.57%, 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 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 86.8% on time across 883 flights, 7 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 7 points of difference.

One caution: this is a thin sample. 882 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking United on DEN to PIT

Put together: treat all of this as provisional. 882 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 79.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 876 completed flights over 12 months sit behind that.

Related

Where to go next

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.