Carrier route record
WNPIT→DEN
Southwest Airlines · Pittsburgh to Denver
- Flights
- 768
- Period
- September 2025 to August 2026
- Share of route
- 47%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on PIT to DEN sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 768 flights, with a median arrival 1 minute early.
The US average over the same twelve months is 77.3%, so there is little to separate Southwest on PIT to DEN from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.6%
Arrivals under 15 minutes late, of 760 completed flights
Avg delay
57 min
Across delayed arrivals only, not all flights
Cancelled
0.78%
National rate is 1.89%
Whole route
80.8%
Every carrier on PIT to DEN, 1,623 flights
These figures cover 768 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Carrier by carrier
Southwest against every carrier on PIT to DEN
Southwest flew 768 of the 1,623 flights on PIT to DEN, about 47% of it. Its 74.6% on time is 6 points worse than the route as a whole, which runs 80.8%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 86.4% to Southwest at 74.6%. 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.
| 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 (this page) | 768 | 74.6% | 57 min | 0.78% | C+ |
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Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 36 points, against half a point between the best and worst carrier.
- 5am–8am275 flights93.1%
- 8am–11am26 flights—
- 11am–2pm92 flights76.9%
- 2pm–5pm64 flights61.9%
- 5pm–8pm262 flights57.1%
- 8pm–5am49 flights68.8%
Scale runs 50% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 57.1% 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 5am–8am window is the busiest, with 275 flights scheduled in it.
Across the year
Southwest on PIT to DEN through the year
August is the worst month at 63.6% on time, 24 points below April, the best at 87.7%. 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 85 flights.
Across the week, Tuesday is the strongest day at 78.9% on time and Saturday the weakest at 70.7%, a spread of 8 points.
Arrival by arrival
How late Southwest on PIT to DEN runs when it is late
The 193 late arrivals split 67 under half an hour, 68 between 30 and 60 minutes, and 58 an hour or more.
- 15+ min early149 flights19.6%
- Within 15 min418 flights55.0%
- 15–29 min late67 flights8.8%
- 30–59 min late68 flights8.9%
- 1–2 hours late42 flights5.5%
- 2+ hours late16 flights2.1%
Scale runs 0% to 100%.
Share of 760 completed flights by arrival against schedule.
53 of 214 late departures made up the time and arrived on time, 25% of them. 32 flights left on time and still arrived late.
The worst days
Worst days for Southwest on PIT to DEN
The latest arrival of the period was on 18 May 2026, 5 hours 11 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. On four of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 18 May 2026 | 5 hours 11 minutes | Late-arriving aircraft |
| 9 July 2026 | 4 hours 34 minutes | Carrier |
| 28 March 2026 | 4 hours 8 minutes | Carrier |
| 25 August 2026 | 4 hours 2 minutes | Carrier |
| 11 February 2026 | 3 hours 58 minutes | Carrier |
Delay causes
Why Southwest runs late on this route
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 11,000 reported delay minutes.
- 38%Late-arriving aircraft
- 32%National Airspace System
- 27%Carrier
- 4%Extreme weather
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 10 to one. The split is drawn from 10,995 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 0.78%, 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 costs
7.6% 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 65.4% on time across 768 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.
One caution: this is a thin sample. 768 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 Southwest on PIT to DEN
Put together: treat all of this as provisional. 768 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 74.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 760 completed flights over 12 months sit behind that.
Related
Where to go next
- PIT to DEN, every carrier
- Southwest on DEN to PIT, the return leg
- United Airlines on PIT to DEN86.4%
- Southwest Airlines network-wide record
- Pittsburgh International (PIT) delay statistics
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
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.