Route reliability record

SLC→LAX

Salt Lake City to Los Angeles

Flights: 4,146
Period: July 2025 to June 2026
Distance: 590 mi
Carriers: 6

This route earns a A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs about an hour. That rests on 4,146 flights, of which SkyWest Airlines flew 691 at 89.6% on time.

SkyWest Airlines is the most reliable of the four carriers covered here at 89.6% on time across 691 flights.

On time

86.2%

Arrivals under 15 minutes late, of 4,126 completed flights

Avg delay

55 min

Across delayed arrivals only, not all flights

Cancelled

0.46%

National rate is 1.81%

Best carrier

SkyWest

89.6% on time across 691 flights

These figures cover 4,146 flights between July 2025 and June 2026. The median arrival is 10 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

Which airline is most reliable on SLC to LAX

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 89.6% of the time; Southwest Airlines manages 80.4%. Sample sizes sit next to every figure, because a two-point gap across 374 flights means less than a ten-point one.

On-time performance by carrier on SLC to LAX
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlinesthin sample	148	91.9%	34 min	0.00%	A+
Spirit Airlinesthin sample	23	90.9%	29 min	4.35%	A−
SkyWest Airlines	691	89.6%	78 min	0.00%	A+
Frontier Airlines	456	88.4%	74 min	1.54%	A
Delta Air Lines	2,454	85.4%	51 min	0.41%	A+
Southwest Airlines	374	80.4%	46 min	0.27%	B+

SkyWest leads Southwest by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Departure window

The best time of day to leave

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 4,146 flights.

5am–8am568 flights91.1%
8am–11am751 flights91.6%
11am–2pm717 flights85.3%
2pm–5pm691 flights83.6%
5pm–8pm663 flights84.6%
8pm–5am756 flights81.9%

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

Book the morning departure. Flights leaving between 8am–11am arrive on time 91.6% of the time, against 81.9% for the overnight window. That is 10 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 756 flights scheduled in it.

Across the year

When delays peak on this route

Twelve months, one bar each, drawn from the same 4,146 flights. The strip shows how much of this route's record is set by the calendar rather than by the operation.

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

July is the worst month at 79.5% on time, 11 points below November, the best at 90.0%. 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 422 flights.

Across the week, Wednesday is the strongest day at 89.4% on time and Sunday the weakest at 83.5%. 6 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Carrier accounts for 49% of the 31,000 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
49%
Late-arriving aircraft
35%
National Airspace System
12%
Extreme weather
4%

35% 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 31,000 reported delay minutes here, that single category outweighs weather by 10 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 31,384 reported delay minutes.

The largest share of delay minutes, 49%, 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 15,000 of the 31,000 delay minutes reported here.

Cancellations are rare at 0.46%, 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 actually costs

Badly late arrivals are rare here: only 3.5% 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 590 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 87.7% on time across 4,144 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 4,146 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking this route

Put together: take the 8am–11am departure, avoid July if the dates are flexible, and if two carriers are within a few dollars of each other, SkyWest is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 10 points, which is the most any booking decision can do. 4,126 completed flights over 12 months sit behind that.

Common questions

SLC to LAX questions

How often is SLC to LAX delayed?

About one flight in seven arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 13.8% of the 4,146 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on SLC to LAX?

SkyWest Airlines leads at 89.6% on time across 691 flights. Southwest Airlines is at the other end on 80.4%, a gap of 9 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on SLC to LAX?

The 8am–11am departure window is the strongest at 91.6% on time. The 8pm–5am window is the weakest at 81.9%, 10 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.

How bad are July delays on SLC to LAX?

July is the weakest month at 79.5% on time, compared with 90.0% in November. Across the year that is 11 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. SLC to LAX and LAX to SLC are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures