Route reliability record

LAS→SLC

Las Vegas to Salt Lake City

Flights: 3,741
Period: July 2025 to June 2026
Distance: 368 mi
Carriers: 5

This route lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrive 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 3,741 flights, of which Frontier Airlines flew 514 at 89.5% on time.

Frontier Airlines is the most reliable of the three carriers covered here at 89.5% on time across 514 flights.

On time

82.8%

Arrivals under 15 minutes late, of 3,713 completed flights

Avg delay

61 min

Across delayed arrivals only, not all flights

Cancelled

0.70%

National rate is 1.81%

Best carrier

Frontier

89.5% on time across 514 flights

These figures cover 3,741 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

Which airline is most reliable on LAS to SLC

The choice of carrier is not cosmetic here. Frontier Airlines arrives on time 89.5% of the time; Southwest Airlines manages 76.5%. Sample sizes sit next to every figure, because a two-point gap across 1,443 flights means less than a ten-point one.

On-time performance by carrier on LAS to SLC
Airline	Flights	On time	Avg delay	Cancelled	Grade
Frontier Airlines	514	89.5%	76 min	1.36%	A
Delta Air Lines	1,713	86.4%	71 min	0.58%	A+
SkyWest Airlinesthin sample	5	80.0%	37 min	0.00%	B+
Spirit Airlinesthin sample	66	76.6%	97 min	3.03%	B−
Southwest Airlines	1,443	76.5%	51 min	0.49%	B+

The spread between Frontier and Southwest is 13 points, wide enough that it should decide the booking. On a hundred trips that is 13 more arrivals inside the on-time window.

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 30 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am715 flights94.2%
8am–11am673 flights91.2%
11am–2pm689 flights83.8%
2pm–5pm456 flights78.0%
5pm–8pm875 flights75.8%
8pm–5am333 flights64.7%

Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 64.7% on time, against 94.2% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 875 flights scheduled in it.

Across the year

When delays peak on this route

Twelve months, one bar each, drawn from the same 3,741 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.February best, May worst

June is the worst month at 77.1% on time, 12 points below February, the best at 88.7%. 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 343 flights.

Across the week, Saturday is the strongest day at 88.6% on time and Sunday the weakest at 77.8%. 11 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. Late-arriving aircraft accounts for 60% of the 39,000 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.

Late-arriving aircraft
60%
Carrier
30%
National Airspace System
10%
Extreme weather
0%

60% 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 39,000 reported delay minutes here, that single category outweighs weather by 60 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 38,897 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 94.2% on time here.

Cancellations are rare at 0.70%, 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

5.3% 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 are the about an hour kind, which a normal layover absorbs.

At 368 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.

The return leg is a different operation and performs like one: it runs 77.9% on time across 3,741 flights, 5 points below 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 5 points of difference.

The sample behind these figures is 3,741 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: avoid the 8pm–5am departure. It runs 64.7% on time against 94.2% for the 5am–8am slot, and that 30 points is the largest single thing you control here. Frontier Airlines is the strongest operator if the fares are close. 3,713 completed flights over 12 months sit behind that.

Common questions

LAS to SLC questions

How often is LAS to SLC delayed?

About one flight in six arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.2% of the 3,741 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.

Which airline is most reliable on LAS to SLC?

Frontier Airlines leads at 89.5% on time across 514 flights. Southwest Airlines is at the other end on 76.5%, a gap of 13 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 LAS to SLC?

The 5am–8am departure window is the strongest at 94.2% on time. The 8pm–5am window is the weakest at 64.7%, 30 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 June delays on LAS to SLC?

June is the weakest month at 77.1% on time, compared with 88.7% in February. Across the year that is 12 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. LAS to SLC and SLC to LAS 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