Route reliability record

SLC→LAS

Salt Lake City to Las Vegas

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

This route lands a B+, level with the national rate of 77.6%. Roughly one flight in five 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 Delta Air Lines flew 1,714 at 80.2% on time.

Delta Air Lines is the most reliable of the three carriers covered here at 80.2% on time across 1,714 flights.

On time

77.9%

Arrivals under 15 minutes late, of 3,714 completed flights

Avg delay

64 min

Across delayed arrivals only, not all flights

Cancelled

0.64%

National rate is 1.81%

Best carrier

Delta

80.2% on time across 1,714 flights

These figures cover 3,741 flights between July 2025 and June 2026. The median arrival is 6 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 LAS

The three carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on SLC to LAS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines	1,714	80.2%	57 min	0.58%	B+
SkyWest Airlinesthin sample	5	80.0%	49 min	0.00%	B+
Frontier Airlines	514	78.6%	129 min	0.97%	B+
Southwest Airlines	1,442	75.2%	48 min	0.49%	B+
Spirit Airlinesthin sample	66	70.3%	92 min	3.03%	C−

No carrier stands out. Delta tops the table at 80.2%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 26 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am430 flights96.3%
8am–11am426 flights91.0%
11am–2pm871 flights75.4%
2pm–5pm693 flights71.7%
5pm–8pm583 flights75.4%
8pm–5am738 flights70.3%

Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 96.3% of the time, against 70.3% for the overnight window. That is 26 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 871 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.January best, June worst

June is the worst month at 71.7% on time, 11 points below January, the best at 82.6%. 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 86.3% on time and Friday the weakest at 71.6%. 15 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 52,000 reported delay minutes.

Late-arriving aircraft
37%
Carrier
32%
National Airspace System
28%
Extreme weather
3%
Security
0%

37% 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 52,000 reported delay minutes here, that single category outweighs weather by 11 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 52,250 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 96.3% on time here.

Cancellations are rare at 0.64%, 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

6.4% 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 82.8% on time across 3,741 flights, 5 points above 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 70.3% on time against 96.3% for the 5am–8am slot, and that 26 points is the largest single thing you control here. Delta Air Lines is the strongest operator if the fares are close. 3,714 completed flights over 12 months sit behind that.

Common questions

SLC to LAS questions

How often is SLC to LAS delayed?

Roughly one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.1% 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 SLC to LAS?

Delta Air Lines leads at 80.2% on time across 1,714 flights. Southwest Airlines is at the other end on 75.2%, a gap of 5 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 LAS?

The 5am–8am departure window is the strongest at 96.3% on time. The 8pm–5am window is the weakest at 70.3%, 26 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 SLC to LAS?

June is the weakest month at 71.7% on time, compared with 82.6% in January. 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 LAS and LAS 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