Carrier performance at one airport
WN→SLC
Southwest Airlines at Salt Lake City International
- Departures
- 11,193
- Period
- September 2025 to August 2026
- Routes
- 16
- Rank here
- #6 of 8
Southwest Airlines at Salt Lake City lands a B+, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about 50 minutes on average. That rests on 11,193 flights, of which SkyWest Airlines flew 36,308 at 89.9% on time.
Measured against the airport rather than the country, Southwest Airlines runs 7 points behind the 84.2% 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
77.6%
11,107 completed departures
Avg delay
49 min
Across delayed flights only
Cancelled
0.54%
At SLC, this carrier only
Rank here
#6
Of 8 carriers clearing the floor at SLC
These figures cover 11,000 flights between September 2025 and August 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 89.9% of the time; JetBlue Airways manages 71.9%. Sample sizes sit next to every figure, because a two-point gap across 584 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlines | 36,308 | 89.9% | 68 min | 0.41% | A+ |
| Delta Air Lines | 54,749 | 83.2% | 60 min | 0.80% | B+ |
| Frontier Airlines | 3,572 | 80.3% | 86 min | 1.40% | B |
| United Airlines | 4,850 | 80.3% | 79 min | 1.09% | B |
| American Airlines | 4,660 | 79.5% | 108 min | 2.17% | B |
| Southwest Airlines (this page) | 11,193 | 77.6% | 49 min | 0.54% | B+ |
| Alaska Airlines | 1,733 | 76.1% | 50 min | 1.33% | B |
| JetBlue Airways | 584 | 71.9% | 83 min | 5.31% | C− |
JetBlue Airways cancels 5.3% 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 16 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 | 2,283 | 72.4% | 49 min | 0.57% | C+ |
| SLC to PHX · Phoenix | 1,854 | 78.8% | 52 min | 0.49% | B+ |
| SLC to LAS · Las Vegas | 1,445 | 75.7% | 49 min | 0.42% | B+ |
| SLC to DAL · Dallas | 670 | 77.5% | 55 min | 1.19% | B |
| SLC to MDW · Chicago | 619 | 82.1% | 36 min | 0.65% | B+ |
| SLC to SMF · Sacramento | 585 | 80.8% | 58 min | 0.34% | B+ |
| SLC to OAK · Oakland | 547 | 87.0% | 57 min | 0.18% | A+ |
| SLC to AUS · Austin | 482 | 76.2% | 50 min | 0.62% | B+ |
| SLC to LGB · Long Beach | 480 | 76.6% | 42 min | 0.21% | B+ |
| SLC to SAN · San Diego | 436 | 72.5% | 48 min | 0.46% | C+ |
| SLC to BWI · Baltimore | 409 | 83.6% | 47 min | 1.22% | B |
| SLC to HOU · Houston | 409 | 81.5% | 46 min | 0.24% | B+ |
| SLC to LAX · Los Angeles | 371 | 80.3% | 44 min | 0.27% | B+ |
| SLC to BNA · Nashvillethin sample | 272 | 85.2% | 41 min | 0.74% | A+ |
| SLC to SJC · San Josethin sample | 208 | 74.3% | 44 min | 0.96% | C+ |
| SLC to BUR · Burbankthin sample | 95 | 76.3% | 53 min | 1.05% | B |
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 18 points between the best and worst carrier.
- 5am–8am2,388 flights96.2%
- 8am–11am1,456 flights81.8%
- 11am–2pm2,608 flights78.5%
- 2pm–5pm2,117 flights66.8%
- 5pm–8pm1,657 flights66.8%
- 8pm–5am967 flights64.8%
Scale runs 55% to 100%.
The 8pm–5am window is where this operation falls apart: 64.8% on time, against 96.2% 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 11am–2pm window is the busiest, with 2,608 flights scheduled in it.
Across the year
Seasonal pattern
August is the worst month at 69.3% on time, 17 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. March was the busiest month here, with 1,011 flights.
Delay causes
What holds this operation up
- 54%Late-arriving aircraft
- 25%National Airspace System
- 19%Carrier
- 2%Extreme weather
- 0%Security
54% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 121,000 reported delay minutes here, that single category outweighs weather by 30 to one. The split is drawn from 121,489 reported delay minutes.
Cancellations are rare at 0.54%, below the national 1.89% 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.
5.2% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 minutes, which a normal layover absorbs.
The sample behind these figures is 11,193 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 August 69.3%, a swing of 17 points. If the dates move at all, move them out of August before you think about anything else. 11,107 completed flights over 12 months sit behind that.
Common questions
Southwest Airlines at SLC
How often is Southwest Airlines at SLC delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.4% of the 11,193 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 50 minutes on average.
Which airline is most reliable on Southwest Airlines at SLC?
SkyWest Airlines leads at 89.9% on time across 36,308 flights. JetBlue Airways is at the other end on 71.9%, a gap of 18 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 96.2% on time. The 8pm–5am window is the weakest at 64.8%, 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 August delays on Southwest Airlines at SLC?
August is the weakest month at 69.3% on time, compared with 86.1% in January. Across the year that is 17 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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.