Carrier route record

OOSAN→SLC

SkyWest Airlines · San Diego to Salt Lake City

Flights: 688
Period: July 2025 to June 2026
Share of route: 23%
Carriers: 4

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

SkyWest on SAN to SLC lands a B+, about a point 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 an hour on average. That is a workable record, not a spotless one. That rests on 688 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,732 at 88.7% on time.

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

On time

78.4%

Arrivals under 15 minutes late, of 682 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

0.73%

National rate is 1.81%

Whole route

84.4%

Every carrier on SAN to SLC, 2,961 flights

These figures cover 688 flights between July 2025 and June 2026. The median arrival is 11 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 SLC

SkyWest flew 688 of the 2,961 flights on SAN to SLC, about 23% of it. Its 78.4% on time is 6 points worse than the route as a whole, which runs 84.4%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from Delta at 88.7% to Southwest at 76.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 88.7% of the time; Southwest Airlines manages 76.6%. Sample sizes sit next to every figure, because a two-point gap across 408 flights means less than a ten-point one.

On-time performance by carrier on SAN to SLC
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	1,732	88.7%	77 min	0.81%	A+
Frontier Airlinesthin sample	133	83.3%	87 min	0.75%	B+
SkyWest Airlines (this page)	688	78.4%	61 min	0.73%	B+
Southwest Airlines	408	76.6%	45 min	0.25%	B+

The spread between Delta and Southwest is 12 points, wide enough that it should decide the booking. On a hundred trips that is 12 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 14 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am—
8am–11am192 flights87.4%
11am–2pm28 flights—
2pm–5pm96 flights73.1%
5pm–8pm270 flights73.6%
8pm–5am102 flights79.2%

Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.

Book the morning departure. Flights leaving between 8am–11am arrive on time 87.4% of the time, against 73.1% for the afternoon window. That is 14 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 270 flights scheduled in it.

Across the year

SkyWest on SAN to SLC through the year

Darker means more delays. Figures are on-time percentages.April best, July worst

July is the worst month at 64.5% on time, 28 points below April, the best at 92.2%. 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. March was the busiest month here, with 94 flights.

Across the week, Wednesday is the strongest day at 85.7% on time and Thursday the weakest at 68.1%. 18 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 49% of the 8,979 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
49%
Carrier
23%
National Airspace System
19%
Extreme weather
10%

49% 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 8,979 reported delay minutes here, that single category outweighs weather by 5 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 8,979 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 87.4% on time here.

Cancellations are rare at 0.73%, 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

7.9% 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 626 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 85.9% on time across 685 flights, 8 points above 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 8 points of difference.

One caution: this is a thin sample. 688 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 SLC

Put together: treat all of this as provisional. 688 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 78.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 682 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