Carrier route record

WNDEN→FAT

Southwest Airlines · Denver to Fresno

Flights: 360
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 DEN to FAT lands a B+, 2 points worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by roughly 40 minutes on average. That is a workable record, not a spotless one. That rests on 360 flights, with a median arrival 2 minutes early.

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

On time

76.0%

Arrivals under 15 minutes late, of 359 completed flights

Avg delay

41 min

Across delayed arrivals only, not all flights

Cancelled

0.28%

National rate is 1.81%

Whole route

81.0%

Every carrier on DEN to FAT, 1,453 flights

These figures cover 360 flights between July 2025 and June 2026. The median arrival is 2 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 DEN to FAT

Southwest flew 360 of the 1,453 flights on DEN to FAT, about 25% of it. Its 76.0% on time is 5 points worse than the route as a whole, which runs 81.0%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from SkyWest at 87.3% to United at 72.3%. 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 FAT
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	749	87.3%	65 min	0.00%	A+
Southwest Airlines (this page)thin sample	360	76.0%	41 min	0.28%	B+
United Airlinesthin sample	344	72.3%	57 min	0.29%	C+

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 26 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–8am5 flights—
8am–11am50 flights92.0%
11am–2pm194 flights78.4%
2pm–5pm105 flights66.3%
5pm–8pm6 flights—
8pm–5am—

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 92.0% of the time, against 66.3% for the afternoon window. That is 26 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 194 flights scheduled in it.

Across the year

Southwest on DEN to FAT through the year

Darker means more delays. Figures are on-time percentages.November best, June worst

June is the worst month at 36.7% on time, 54 points below November, the best at 90.3%. 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. December was the busiest month here, with 33 flights.

Across the week, Tuesday is the strongest day at 81.1% on time and Friday the weakest at 67.3%. 14 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Southwest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 54% of the 3,553 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
40%
National Airspace System
6%

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 3,553 reported delay minutes here, that single category outweighs weather by 54 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 3,553 reported delay minutes.

The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 1,421 of the 3,553 delay minutes reported here.

Cancellations are rare at 0.28%, 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

Badly late arrivals are rare here: only 3.3% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

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 77.7% on time across 359 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. 360 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 DEN to FAT

Put together: treat all of this as provisional. 360 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 76.0% 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.

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.

Key figures