Carrier route record

OOSAN→DEN

SkyWest Airlines · San Diego to Denver

Flights: 342
Period: July 2025 to June 2026
Share of route: 6%
Carriers: 5

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

SkyWest on SAN to DEN lands a B, 2 points better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about 45 minutes on average. That is a workable record, not a spotless one. That rests on 342 flights. The strongest carrier on the route with a full sample, United Airlines, flew 2,081 at 85.4% on time.

United Airlines is the most reliable of the four carriers covered here at 85.4% on time across 2,081 flights.

On time

79.2%

Arrivals under 15 minutes late, of 337 completed flights

Avg delay

45 min

Across delayed arrivals only, not all flights

Cancelled

1.46%

National rate is 1.81%

Whole route

79.2%

Every carrier on SAN to DEN, 5,947 flights

These figures cover 342 flights between July 2025 and June 2026. The median arrival is 8 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 SAN to DEN

SkyWest flew 342 of the 5,947 flights on SAN to DEN, about 6% of it. Its 79.2% on time is about level with the route as a whole at 79.2%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from United at 85.4% to Southwest at 72.4%.

The choice of carrier is not cosmetic here. United Airlines arrives on time 85.4% of the time; Southwest Airlines manages 72.4%. Sample sizes sit next to every figure, because a two-point gap across 2,387 flights means less than a ten-point one.

On-time performance by carrier on SAN to DEN
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	2,081	85.4%	65 min	0.77%	A+
Alaska Airlines	433	83.4%	57 min	1.15%	B
Frontier Airlines	704	81.6%	79 min	1.28%	B
SkyWest Airlines (this page)thin sample	342	79.2%	45 min	1.46%	B
Southwest Airlines	2,387	72.4%	57 min	0.75%	C+

The spread between United and Southwest is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.

Departure window

When SkyWest runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am62 flights87.1%
11am–2pm1 flights—
2pm–5pm92 flights66.3%
5pm–8pm—
8pm–5am187 flights83.0%

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 87.1% of the time, against 66.3% for the afternoon window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 187 flights scheduled in it.

Across the year

SkyWest on SAN to DEN through the year

Oct–Dec 2025119 flights76.7%
Jan–Mar 202680 flights87.3%
Apr–Jun 2026143 flights76.8%

Scale runs 70% to 95%. 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 79.2% on time across 342 flights.

SkyWest on SAN to DEN did not run the same all year. Its best quarter was Jan–Mar 2026 at 87.3% on time and its weakest Oct–Dec 2025 at 76.7%, a swing of 11 points on roughly 114 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Across the week, Saturday is the strongest day at 91.7% on time and Monday the weakest at 67.3%. 24 points is a smaller lever than departure hour, but it is free.

Delay causes

Why SkyWest runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 50% of the 3,128 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
50%
National Airspace System
27%
Carrier
21%
Extreme weather
2%

50% 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 3,128 reported delay minutes here, that single category outweighs weather by 26 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 3,128 reported delay minutes.

The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 87.1% on time here.

Cancellations sit at 1.46% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 4.2% 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 853 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 75.0% on time across 343 flights, 4 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 4 points of difference.

One caution: this is a thin sample. 342 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 SAN to DEN

Put together: treat all of this as provisional. 342 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 79.2% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 337 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