Route reliability record

LAX→SLC

Los Angeles to Salt Lake City

Flights: 4,144
Period: July 2025 to June 2026
Distance: 590 mi
Carriers: 6

This route earns a A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 10 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 4,144 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

87.7%

Arrivals under 15 minutes late, of 4,120 completed flights

Avg delay

75 min

Across delayed arrivals only, not all flights

Cancelled

0.41%

National rate is 1.81%

Best carrier

SkyWest

89.6% on time across 691 flights

These figures cover 4,144 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

Which airline is most reliable on LAX to SLC

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 89.6% of the time; Southwest Airlines manages 81.7%. 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 LAX to SLC
Airline	Flights	On time	Avg delay	Cancelled	Grade
Spirit Airlinesthin sample	23	90.9%	29 min	4.35%	A−
SkyWest Airlines	691	89.6%	87 min	0.00%	A+
United Airlinesthin sample	149	88.6%	65 min	0.00%	A+
Delta Air Lines	2,451	88.5%	79 min	0.41%	A+
Frontier Airlines	456	85.2%	76 min	0.88%	A+
Southwest Airlines	374	81.7%	46 min	0.53%	B+

SkyWest leads Southwest by 8 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 matters more here than the choice of carrier. The gap between the best and worst window is 12 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am797 flights93.7%
8am–11am822 flights87.8%
11am–2pm1,182 flights88.4%
2pm–5pm183 flights81.4%
5pm–8pm1,137 flights84.1%
8pm–5am23 flights—

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 93.7% of the time, against 81.4% for the afternoon window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 1,182 flights scheduled in it.

Across the year

When delays peak on this route

Twelve months, one bar each, drawn from the same 4,144 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.October best, January worst

January is the weak month at 83.9% on time, against 92.0% in October. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. March was the busiest month here, with 423 flights.

Across the week, Tuesday is the strongest day at 91.2% on time and Sunday the weakest at 84.6%. 7 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 58% of the 38,000 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
58%
Late-arriving aircraft
35%
National Airspace System
5%
Extreme weather
1%
Security
0%

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 38,000 reported delay minutes here, that single category outweighs weather by 32 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 37,810 reported delay minutes.

The largest share of delay minutes, 58%, 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 22,000 of the 38,000 delay minutes reported here.

Cancellations are rare at 0.41%, 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 4.5% 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 86.2% on time across 4,146 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 4,144 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 5am–8am departure, avoid January 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 12 points, which is the most any booking decision can do. 4,120 completed flights over 12 months sit behind that.

Common questions

LAX to SLC questions

How often is LAX to SLC delayed?

About one flight in eight arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 12.3% of the 4,144 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.

Which airline is most reliable on LAX to SLC?

SkyWest Airlines leads at 89.6% on time across 691 flights. Southwest Airlines is at the other end on 81.7%, a gap of 8 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 LAX to SLC?

The 5am–8am departure window is the strongest at 93.7% on time. The 2pm–5pm window is the weakest at 81.4%, 12 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 January delays on LAX to SLC?

January is the weakest month at 83.9% on time, compared with 92.0% in October. Across the year that is 8 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. LAX to SLC and SLC to LAX 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