Carrier route record
WNTUL→DEN
Southwest Airlines · Tulsa to Denver
- Flights
- 893
- Period
- July 2025 to June 2026
- Share of route
- 37%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on TUL to DEN lands a B, 5 points better than the national rate of 77.6%. About one flight in six 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 893 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 1,129 at 79.2% on time.
Set against the rest of the country, Southwest's TUL to DEN record is 5 points better than the US average of 77.6%. That gap is worth roughly 48 fewer late arrivals for every thousand flights.
Key figures
On time
82.4%
Arrivals under 15 minutes late, of 883 completed flights
Avg delay
59 min
Across delayed arrivals only, not all flights
Cancelled
1.12%
National rate is 1.81%
Whole route
79.8%
Every carrier on TUL to DEN, 2,430 flights
These figures cover 893 flights between July 2025 and June 2026. The median arrival is 5 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
Southwest against every carrier on TUL to DEN
Southwest flew 893 of the 2,430 flights on TUL to DEN, about 37% of it. Its 82.4% on time is 3 points better than the route as a whole, which runs 79.8%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from Southwest at 82.4% to Frontier at 73.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Southwest Airlines (this page) | 893 | 82.4% | 59 min | 1.12% | B |
| SkyWest Airlines | 1,129 | 79.2% | 74 min | 0.89% | B+ |
| United Airlines | 366 | 75.7% | 45 min | 1.09% | B |
| Frontier Airlinesthin sample | 42 | 73.8% | 64 min | 0.00% | C+ |
No carrier stands out. SkyWest tops the table at 79.2%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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 25 points, against 4 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am277 flights93.4%
- 8am–11am121 flights88.3%
- 11am–2pm129 flights82.8%
- 2pm–5pm24 flights—
- 5pm–8pm222 flights68.5%
- 8pm–5am120 flights77.3%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 93.4% of the time, against 68.5% for the evening window. That is 25 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 277 flights scheduled in it.
Across the year
Southwest on TUL to DEN through the year
July is the worst month at 65.2% on time, 29 points below January, the best at 93.8%. 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 92 flights.
Across the week, Sunday is the strongest day at 86.5% on time and Thursday the weakest at 77.6%. 9 points is a smaller lever than departure hour, but it is free.
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 9,129 reported delay minutes.
- 37%Late-arriving aircraft
- 34%National Airspace System
- 19%Carrier
- 10%Extreme weather
37% 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 9,129 reported delay minutes here, that single category outweighs weather by 4 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 9,129 reported delay minutes.
34% 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 3,073 minutes out of 9,129, against a national NAS share of 21%.
Cancellations sit at 1.12% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
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 541 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 64.1% on time across 893 flights, 18 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 18 points of difference.
One caution: this is a thin sample. 893 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 TUL to DEN
Put together: treat all of this as provisional. 893 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 82.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 883 completed flights over 12 months sit behind that.
Related
Where to go next
- TUL to DEN, every carrier
- Southwest on DEN to TUL, the return leg
- SkyWest Airlines on TUL to DEN79.2%
- United Airlines on TUL to DEN75.7%
- Southwest Airlines network-wide record
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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.