Carrier route record

OOSTL→DEN

SkyWest Airlines · St. Louis to Denver

Flights: 142
Period: July 2025 to June 2026
Share of route: 4%
Carriers: 4

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

SkyWest on STL to DEN earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 142 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,071 at 76.6% on time.

Set against the rest of the country, SkyWest's STL to DEN record is 10 points better than the US average of 77.6%. That gap is worth roughly 95 fewer late arrivals for every thousand flights.

On time

87.1%

Arrivals under 15 minutes late, of 140 completed flights

Avg delay

60 min

Across delayed arrivals only, not all flights

Cancelled

0.70%

National rate is 1.81%

Whole route

74.9%

Every carrier on STL to DEN, 3,655 flights

These figures cover 142 flights between July 2025 and June 2026. The median arrival is 12 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

SkyWest against every carrier on STL to DEN

SkyWest flew 142 of the 3,655 flights on STL to DEN, about 4% of it. Its 87.1% on time is 12 points better than the route as a whole, which runs 74.9%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from SkyWest at 87.1% to Southwest at 73.3%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The two carriers here are closely matched: 3 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.

On-time performance by carrier on STL to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines (this page)thin sample	142	87.1%	60 min	0.70%	A+
United Airlines	1,071	76.6%	91 min	0.56%	B+
Frontier Airlinesthin sample	277	74.5%	83 min	1.08%	C
Southwest Airlines	2,165	73.3%	60 min	0.23%	C+

No carrier stands out. United tops the table at 76.6%, 3 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

When SkyWest 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 142 flights.

There are not enough flights in each departure window to split SkyWest's STL to DEN record by time of day without the percentages moving on noise. The headline rate of 87.1% is the reliable figure here.

Across the year

SkyWest on STL to DEN through the year

Jul–Sep 202592 flights84.6%
Oct–Dec 202525 flights—
Jan–Mar 202624 flights—
Apr–Jun 20261 flights—

Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 87.1% on time across 142 flights.

Split by quarter, SkyWest on STL to DEN logged 92 flights in Jul–Sep 2025, 25 flights in Oct–Dec 2025, 24 flights in Jan–Mar 2026 and 1 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 87.1% annual figure is the one to use.

Delay causes

Why SkyWest runs late on this route

One category carries most of the weight here. Carrier accounts for 92% of the 1,075 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.

Carrier
92%
Extreme weather
8%

The largest share of delay minutes, 92%, 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 990 of the 1,075 delay minutes reported here. The split is drawn from 1,075 reported delay minutes.

Cancellations are rare at 0.70%, 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 2.9% 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 770 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 77.0% on time across 141 flights, 10 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 10 points of difference.

One caution: this is a thin sample. 142 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 SkyWest on STL to DEN

Put together: treat all of this as provisional. 142 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 87.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 140 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