Carrier route record
WNFAT→DEN
Southwest Airlines · Fresno to Denver
- Flights
- 359
- Period
- July 2025 to June 2026
- Share of route
- 25%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on FAT to DEN lands a B+, level with the national rate of 77.6%. Roughly one flight in four 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 359 flights, with a median arrival 7 minutes early.
The US average over the same twelve months is 77.6%, so there is little to separate Southwest on FAT 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
77.7%
Arrivals under 15 minutes late, of 359 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
Whole route
87.8%
Every carrier on FAT to DEN, 1,450 flights
These figures cover 359 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
Southwest against every carrier on FAT to DEN
Southwest flew 359 of the 1,450 flights on FAT to DEN, about 25% of it. Its 77.7% on time is 10 points worse than the route as a whole, which runs 87.8%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from United at 93.3% to Southwest at 77.7%. 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlinesthin sample | 344 | 93.3% | 86 min | 0.29% | A+ |
| SkyWest Airlines | 747 | 90.2% | 72 min | 0.00% | A+ |
| Southwest Airlines (this page)thin sample | 359 | 77.7% | 63 min | 0.00% | B+ |
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 32 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am9 flights—
- 8am–11am23 flights—
- 11am–2pm295 flights78.6%
- 2pm–5pm32 flights46.9%
- 5pm–8pm—
- 8pm–5am—
Scale runs 40% to 85%. Rows with fewer than 30 flights show a dash.
The best window here is not the first bank but the 11am–2pm slot at 78.6% on time, ahead of 2pm–5pm at 46.9%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 11am–2pm window is the busiest, with 295 flights scheduled in it.
Across the year
Southwest on FAT to DEN through the year
July is the worst month at 45.2% on time, 43 points below December, the best at 87.9%. 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. December was the busiest month here, with 33 flights.
Across the week, Sunday is the strongest day at 86.5% on time and Friday the weakest at 67.3%. 19 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 5,034 reported delay minutes.
- 39%National Airspace System
- 36%Late-arriving aircraft
- 21%Carrier
- 3%Extreme weather
36% 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 5,034 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 5,034 reported delay minutes.
39% 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 1,981 minutes out of 5,034, against a national NAS share of 21%.
Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
7.5% 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 844 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 runs 76.0% on time across 360 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 359 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 FAT to DEN
Put together: treat all of this as provisional. 359 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 77.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 359 completed flights over 12 months sit behind that.
Related
Where to go next
- FAT to DEN, every carrier
- Southwest on DEN to FAT, the return leg
- United Airlines on FAT to DEN93.3%
- SkyWest Airlines on FAT to DEN90.2%
- 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.