Carrier route record
WNSMF→SAN
Southwest Airlines · Sacramento to San Diego
- Flights
- 3,810
- Period
- July 2025 to June 2026
- Share of route
- 74%
- 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 SAN sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land roughly 50 minutes behind schedule. That rests on 3,810 flights, with a median arrival 2 minutes late.
The national on-time rate over the same period is 77.6%, so Southwest on SMF to SAN runs 7 points behind the country as a whole. Across a thousand flights that is about 67 extra late arrivals.
Key figures
On time
70.9%
Arrivals under 15 minutes late, of 3,780 completed flights
Avg delay
48 min
Across delayed arrivals only, not all flights
Cancelled
0.55%
National rate is 1.81%
Whole route
73.3%
Every carrier on SMF to SAN, 5,182 flights
These figures cover 3,810 flights between July 2025 and June 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
Carrier by carrier
Southwest against every carrier on SMF to SAN
Southwest flew 3,810 of the 5,182 flights on SMF to SAN, most of the route. Its 70.9% on time is 2 points worse than the route as a whole, which runs 73.3%. Ranked by on-time rate it is last of three carriers on the route, where the range runs from Alaska at 85.5% to Southwest at 70.9%. 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 |
|---|---|---|---|---|---|
| Alaska Airlinesthin sample | 185 | 85.5% | 38 min | 3.24% | A− |
| SkyWest Airlines | 1,187 | 79.0% | 54 min | 1.77% | B |
| Southwest Airlines (this page) | 3,810 | 70.9% | 48 min | 0.55% | C+ |
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 28 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–8am595 flights86.8%
- 8am–11am680 flights84.3%
- 11am–2pm695 flights71.2%
- 2pm–5pm795 flights61.2%
- 5pm–8pm754 flights60.8%
- 8pm–5am291 flights59.1%
Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 59.1% on time, against 86.8% 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 2pm–5pm window is the busiest, with 795 flights scheduled in it.
Across the year
Southwest on SMF to SAN through the year
June is the worst month at 57.8% on time, 22 points below September, the best at 80.2%. 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. July was the busiest month here, with 346 flights.
Across the week, Tuesday is the strongest day at 80.9% on time and Friday the weakest at 62.9%. 18 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 47% of the 53,000 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.
- 47%Late-arriving aircraft
- 28%National Airspace System
- 24%Carrier
- 1%Extreme weather
- 0%Security
47% 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 53,000 reported delay minutes here, that single category outweighs weather by 47 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 52,700 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 86.8% on time here.
Cancellations are rare at 0.55%, 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
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 last roughly 50 minutes, which a normal layover absorbs.
At 480 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 75.5% on time across 3,807 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 3,810 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 Southwest on SMF to SAN
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 80.2% on time and June 57.8%, a swing of 22 points. If the dates move at all, move them out of June before you think about anything else. 3,780 completed flights over 12 months sit behind that.
Related
Where to go next
- SMF to SAN, every carrier
- Southwest on SAN to SMF, the return leg
- Alaska Airlines on SMF to SAN85.5%
- SkyWest Airlines on SMF to SAN79.0%
- Southwest Airlines network-wide record
- Sacramento International (SMF) delay statistics
- San Diego International (SAN) 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.