Carrier route record

F9SAN→SLC

Frontier Airlines · San Diego to Salt Lake City

Flights: 133
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 Frontier Airlines.

Frontier on SAN to SLC lands a B+, 6 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 133 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,732 at 88.7% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 88.7% on time across 1,732 flights.

On time

83.3%

Arrivals under 15 minutes late, of 132 completed flights

Avg delay

87 min

Across delayed arrivals only, not all flights

Cancelled

0.75%

National rate is 1.81%

Whole route

84.4%

Every carrier on SAN to SLC, 2,961 flights

These figures cover 133 flights between July 2025 and June 2026. The median arrival is 9 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 SAN to SLC

Frontier flew 133 of the 2,961 flights on SAN to SLC, about 4% of it. Its 83.3% on time is about level with the route as a whole at 84.4%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Delta at 88.7% to Southwest at 76.6%.

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 Airlines (this page)thin sample	133	83.3%	87 min	0.75%	B+
SkyWest Airlines	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 Frontier runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 10 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am12 flights—
8am–11am37 flights83.3%
11am–2pm48 flights85.4%
2pm–5pm4 flights—
5pm–8pm32 flights75.0%
8pm–5am—

Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.

The best window here is not the first bank but the 11am–2pm slot at 85.4% on time, ahead of 5pm–8pm at 75.0%. Where the curve peaks mid-day rather than at dawn, the constraint is usually congestion at one end rather than the aircraft's own rotation. The 11am–2pm window is the busiest, with 48 flights scheduled in it.

Across the year

Frontier on SAN to SLC through the year

Jul–Sep 202539 flights79.5%
Oct–Dec 202537 flights81.1%
Jan–Mar 202637 flights89.2%
Apr–Jun 202620 flights—

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 83.3% on time across 133 flights.

Quarter by quarter Frontier on SAN to SLC held fairly steady: 79.5% in Jul–Sep 2025, 81.1% in Oct–Dec 2025 and 89.2% in Jan–Mar 2026. A spread of 10 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Across the week, Monday is the strongest day at 90.9% on time and Sunday the weakest at 76.7%. 14 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 61% of the 1,902 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
61%
Carrier
32%
National Airspace System
7%
Extreme weather
1%

61% 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 1,902 reported delay minutes here, that single category outweighs weather by 61 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 1,902 reported delay minutes.

Cancellations are rare at 0.75%, 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

6.8% 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 an hour and a half, 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 runs 84.6% 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 SAN to SLC

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 83.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 132 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