Carrier route record
WNSMF→SLC
Southwest Airlines · Sacramento to Salt Lake City
- Flights
- 576
- Period
- July 2025 to June 2026
- Share of route
- 27%
- Carriers
- 3
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Southwest Airlines.
Southwest on SMF to SLC lands a B+, 4 points better than the national rate of 77.6%. Roughly one flight in five arrives 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 576 flights, with a median arrival 7 minutes early.
Set against the rest of the country, Southwest's SMF to SLC record is 4 points better than the US average of 77.6%. That gap is worth roughly 40 fewer late arrivals for every thousand flights.
Key figures
On time
81.6%
Arrivals under 15 minutes late, of 575 completed flights
Avg delay
60 min
Across delayed arrivals only, not all flights
Cancelled
0.17%
National rate is 1.81%
Whole route
87.6%
Every carrier on SMF to SLC, 2,158 flights
These figures cover 576 flights between July 2025 and June 2026. The median arrival is 7 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
Southwest against every carrier on SMF to SLC
Southwest flew 576 of the 2,158 flights on SMF to SLC, about 27% of it. Its 81.6% on time is 6 points worse than the route as a whole, which runs 87.6%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from SkyWest at 91.8% to Southwest at 81.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 73 | 91.8% | 64 min | 0.00% | A+ |
| Delta Air Lines | 1,509 | 89.7% | 80 min | 0.86% | A+ |
| Southwest Airlines (this page) | 576 | 81.6% | 60 min | 0.17% | B+ |
Departure window
When Southwest runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 42 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am94 flights94.7%
- 8am–11am205 flights95.6%
- 11am–2pm52 flights90.2%
- 2pm–5pm29 flights—
- 5pm–8pm113 flights54.0%
- 8pm–5am83 flights72.3%
Scale runs 45% to 100%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 54.0% on time, against 95.6% for the 8am–11am 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 8am–11am window is the busiest, with 205 flights scheduled in it.
Across the year
Southwest on SMF to SLC through the year
November is the best month on the calendar at 93.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 57 flights.
Across the week, Saturday is the strongest day at 94.2% on time and Friday the weakest at 70.4%. 24 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Southwest runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 70% of the 6,397 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.
- 70%Late-arriving aircraft
- 26%Carrier
- 4%National Airspace System
70% 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 6,397 reported delay minutes here, that single category outweighs weather by 70 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 6,397 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 95.6% on time here.
Cancellations are rare at 0.17%, 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 costs
7.1% 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 last about an hour, which a normal layover absorbs.
The 532 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 81.7% on time across 576 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 576 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Southwest on SMF to SLC
Put together: treat all of this as provisional. 576 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 81.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 575 completed flights over 12 months sit behind that.
Related
Where to go next
- SMF to SLC, every carrier
- Southwest on SLC to SMF, the return leg
- Delta Air Lines on SMF to SLC89.7%
- Southwest Airlines network-wide record
- Sacramento International (SMF) delay statistics
- Salt Lake City International (SLC) delay statistics
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.