Carrier performance at one airport
WN→SLC
Southwest Airlines at Salt Lake City International
- Departures
- 11,356
- Period
- June 2025 to May 2026
- Routes
- 17
- Rank here
- #5 of 8
Southwest Airlines at Salt Lake City lands a B+, about a point better than the national rate of 77.4%. About one flight in five arrive 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 11,356 flights, of which SkyWest Airlines flew 36,165 at 90.8% on time.
Measured against the airport rather than the country, Southwest Airlines runs 6 points behind the 84.6% weighted average across all carriers at SLC. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
78.3%
11,261 completed departures
Avg delay
51 min
Across delayed flights only
Cancelled
0.60%
At SLC, this carrier only
Rank here
#5
Of 8 carriers clearing the floor at SLC
These figures cover 11,000 flights between June 2025 and May 2026. The median arrival is 5 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.
Against the competition
Every carrier at SLC, ranked
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 90.8% of the time; Alaska Airlines manages 73.6%. Sample sizes sit next to every figure, because a two-point gap across 1,578 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 36,165 | 90.8% | 64 min | 0.43% | A+ |
| Delta Air Lines | 54,627 | 83.5% | 62 min | 0.75% | B+ |
| United Airlines | 4,851 | 80.0% | 72 min | 0.97% | B+ |
| Frontier Airlines | 3,432 | 79.1% | 88 min | 1.46% | B |
| Southwest Airlines (this page) | 11,356 | 78.3% | 51 min | 0.60% | B+ |
| American Airlines | 4,617 | 78.2% | 99 min | 2.43% | B |
| JetBlue Airways | 575 | 74.0% | 90 min | 3.48% | C− |
| Alaska Airlines | 1,578 | 73.6% | 48 min | 1.84% | C |
JetBlue Airways cancels 3.5% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where Southwest Airlines flies from SLC
Southwest Airlines operates 17 routes out of SLC with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SLC to DEN · Denver | 2,346 | 72.0% | 53 min | 0.68% | C+ |
| SLC to PHX · Phoenix | 1,859 | 80.6% | 54 min | 0.59% | B+ |
| SLC to LAS · Las Vegas | 1,442 | 75.4% | 48 min | 0.49% | B+ |
| SLC to DAL · Dallas | 674 | 78.3% | 61 min | 1.04% | B |
| SLC to OAK · Oakland | 622 | 85.2% | 53 min | 0.16% | A+ |
| SLC to MDW · Chicago | 617 | 84.7% | 36 min | 0.81% | B+ |
| SLC to SMF · Sacramento | 573 | 82.7% | 57 min | 0.35% | B+ |
| SLC to AUS · Austin | 469 | 80.0% | 53 min | 0.64% | B+ |
| SLC to LGB · Long Beach | 451 | 77.3% | 40 min | 0.22% | B+ |
| SLC to BWI · Baltimore | 410 | 81.9% | 60 min | 1.22% | B |
| SLC to HOU · Houston | 409 | 82.5% | 48 min | 0.24% | B+ |
| SLC to SAN · San Diego | 408 | 74.8% | 53 min | 0.25% | C+ |
| SLC to LAX · Los Angeles | 374 | 78.6% | 45 min | 0.27% | B+ |
| SLC to BNA · Nashvillethin sample | 275 | 87.1% | 43 min | 0.73% | A+ |
| SLC to SJC · San Josethin sample | 235 | 80.2% | 49 min | 1.28% | B |
| SLC to BUR · Burbankthin sample | 146 | 72.0% | 50 min | 1.37% | C |
| SLC to MCO · Orlandothin sample | 31 | 71.0% | 62 min | 0.00% | C+ |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 31 points, against 17 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am2,341 flights95.9%
- 8am–11am1,533 flights82.7%
- 11am–2pm2,548 flights79.6%
- 2pm–5pm2,277 flights68.4%
- 5pm–8pm1,741 flights68.6%
- 8pm–5am916 flights65.2%
Scale runs 55% to 100%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 95.9% of the time, against 65.2% for the overnight window. That is 31 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.
Across the year
Seasonal pattern
July is the worst month at 70.9% on time, 15 points below January, the best at 86.1%. 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.
Delay causes
What holds this operation up
- 52%Late-arriving aircraft
- 27%National Airspace System
- 20%Carrier
- 2%Extreme weather
- 0%Security
52% 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 125,000 reported delay minutes here, that single category outweighs weather by 31 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.
Cancellations are rare at 0.60%, below the national 1.80% 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.
5.4% of arrivals land an hour or more late, close to the national 8.2%. 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 roughly 50 minutes kind, which a normal layover absorbs.
The sample behind these figures is 11,356 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.
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 86.1% on time and July 70.9%, a swing of 15 points. If the dates move at all, move them out of July before you think about anything else.
Common questions
Southwest Airlines at SLC
How often is Southwest Airlines at SLC delayed?
About 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 21.7% of the 11,356 flights in this analysis, against 22.6% nationally. Delayed flights are late by roughly 50 minutes on average.
Which airline is most reliable on Southwest Airlines at SLC?
SkyWest Airlines leads at 90.8% on time across 36,165 flights. Alaska Airlines is at the other end on 73.6%, a gap of 17 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 Southwest Airlines at SLC?
The 5am–8am departure window is the strongest at 95.9% on time. The 8pm–5am window is the weakest at 65.2%, 31 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 Southwest Airlines at SLC?
July is the weakest month at 70.9% on time, compared with 86.1% in January. Across the year that is 15 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.