Carrier route record

F9SLC→SAN

Frontier Airlines · Salt Lake City to San Diego

Flights: 133
Period: July 2025 to June 2026
Share of route: 4%
Carriers: 5

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

Frontier on SLC to SAN earns a B. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 50 minutes. That rests on 133 flights. The strongest carrier on the route with a full sample, SkyWest Airlines, flew 685 at 85.9% on time.

SkyWest Airlines is the most reliable of the three carriers covered here at 85.9% on time across 685 flights.

On time

84.6%

Arrivals under 15 minutes late, of 130 completed flights

Avg delay

50 min

Across delayed arrivals only, not all flights

Cancelled

2.26%

National rate is 1.81%

Whole route

83.2%

Every carrier on SLC to SAN, 2,958 flights

These figures cover 133 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

Frontier against every carrier on SLC to SAN

Frontier flew 133 of the 2,958 flights on SLC to SAN, about 4% of it. Its 84.6% on time is about level with the route as a whole at 83.2%. Ranked by on-time rate it is number three of five carriers on the route, where the range runs from Alaska at 100.0% to Southwest at 75.8%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 85.9% of the time; Southwest Airlines manages 75.8%. 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 SLC to SAN
Airline	Flights	On time	Avg delay	Cancelled	Grade
Alaska Airlinesthin sample	1	100.0%	—	0.00%	A+
SkyWest Airlines	685	85.9%	58 min	1.02%	A
Frontier Airlines (this page)thin sample	133	84.6%	50 min	2.26%	B
Delta Air Lines	1,731	83.8%	55 min	0.81%	B+
Southwest Airlines	408	75.8%	47 min	0.25%	B+

SkyWest leads Southwest by 10 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Departure window

When Frontier 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 133 flights.

5am–8am—
8am–11am59 flights88.1%
11am–2pm14 flights—
2pm–5pm—
5pm–8pm46 flights84.1%
8pm–5am14 flights—

Scale runs 75% to 95%. Rows with fewer than 30 flights show a dash.

The early departures do better, though not dramatically: 88.1% on time for the 8am–11am window against 84.1% for 5pm–8pm. Worth taking if the schedule allows, not worth an extra connection. The 8am–11am window is the busiest, with 59 flights scheduled in it.

Across the year

Frontier on SLC to SAN through the year

Jul–Sep 202539 flights92.3%
Oct–Dec 202537 flights94.4%
Jan–Mar 202637 flights74.3%
Apr–Jun 202620 flights—

Scale runs 65% to 100%. 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 84.6% on time across 133 flights.

Frontier on SLC to SAN did not run the same all year. Its best quarter was Oct–Dec 2025 at 94.4% on time and its weakest Jan–Mar 2026 at 74.3%, a swing of 20 points on roughly 44 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.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 47% of the 991 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
47%
National Airspace System
45%
Carrier
8%

47% 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 991 reported delay minutes here, that single category outweighs weather by 47 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 991 reported delay minutes.

45% 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 445 minutes out of 991, against a national NAS share of 21%.

Cancellations sit at 2.26% 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 4.6% 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 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 runs 83.3% on time across 133 flights, within about a point 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. 133 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 Frontier on SLC to SAN

Put together: treat all of this as provisional. 133 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 84.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 130 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