Route reliability record
SMF→SAN
Sacramento to San Diego
- Flights
- 5,179
- Period
- September 2025 to August 2026
- Distance
- 480 mi
- Carriers
- 3
This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 8 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 5,179 SMF to SAN flights, of which SkyWest Airlines flew 1,138 at 75.6% on time.
Best time to fly SMF to SAN: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 86.1% of the time and Saturday flights 81.6%, against 69.8% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 8 points behind the country as a whole. Across a thousand flights that is about 75 extra late arrivals.
Key figures
On time
69.8%
Arrivals under 15 minutes late, of 5,113 completed flights
Avg delay
46 min
Across delayed arrivals only, not all flights
Cancelled
1.02%
National rate is 1.89%
Best carrier
SkyWest
75.6% on time across 1,138 flights
These figures cover 5,179 flights between September 2025 and August 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.
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Carrier by carrier
Which airline is most reliable on SMF to SAN
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 75.6% of the time; Southwest Airlines manages 67.1%. Sample sizes sit next to every figure, because a two-point gap across 3,794 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlinesthin sample | 247 | 84.6% | 35 min | 2.83% | B |
| SkyWest Airlines | 1,138 | 75.6% | 49 min | 2.02% | B |
| Southwest Airlines | 3,794 | 67.1% | 46 min | 0.61% | C+ |
SkyWest leads Southwest by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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Best ways to make this trip
The most reliable ways to fly Sacramento to San Diego
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SMF → SANSacramento to San Diego | SkyWest Airlines | 74.1% | 75.6% | 2.02% | 5am–8am, Tue | — |
| 2. SMF → SANSacramento to San Diego | Southwest Airlines | 66.7% | 67.1% | 0.61% | 5am–8am, Sat | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 32 points, against 9 points between the best and worst carrier.
- 5am–8am946 flights86.1%
- 8am–11am902 flights78.9%
- 11am–2pm958 flights68.5%
- 2pm–5pm1,033 flights62.7%
- 5pm–8pm972 flights60.3%
- 8pm–5am368 flights53.9%
Scale runs 45% to 90%.
The 8pm–5am window is where this operation falls apart: 53.9% on time, against 86.1% 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 1,033 flights scheduled in it.
Explore
Filter SMF to SAN by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On SMF to SAN, the best departure window is 5am–8am at 86.1% on time and the worst is 8pm–5am at 53.9%, a wide gap of 32.2 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am86.1%
- 8–11am78.9%
- 11am–2pm68.5%
- 2–5pm62.7%
- 5–8pm60.3%
- 8pm–5am53.9%
best all US flightsScale 45% to 95%.
Across the year
When delays peak on this route
This route's year swings by 29 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
August is the worst month at 51.4% on time, 29 points below March, the best at 80.7%. 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 469 flights.
Across the week, Saturday is the strongest day at 81.6% on time and Friday the weakest at 60.5%, a spread of 21 points.
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 71,000 reported delay minutes.
- 41%Late-arriving aircraft
- 36%National Airspace System
- 21%Carrier
- 1%Extreme weather
- 0%Security
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 71,000 reported delay minutes here, that single category outweighs weather by 30 to one. The split is drawn from 71,358 reported delay minutes.
36% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 26,000 minutes out of 71,000, against a national NAS share of 21%.
Cancellations sit at 1.02% against a national 1.89%, which is ordinary. Diversions add another 0.25%.
Connections and stage length
What a delay here actually costs
6.3% 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 roughly 45 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 74.5% on time across 5,181 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 5,179 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.
Work out the risk of missing a connection in SAN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 80.7% on time and August 51.4%, a swing of 29 points. If the dates move at all, move them out of August before you think about anything else. 5,113 completed flights over 12 months sit behind that.
Common questions
SMF to SAN questions
How often is SMF to SAN delayed?
Roughly one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 30.2% of the 5,179 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 45 minutes on average.
Which airline is most reliable on SMF to SAN?
SkyWest Airlines leads at 75.6% on time across 1,138 flights. Southwest Airlines is at the other end on 67.1%, a gap of 9 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 SMF to SAN?
The 5am–8am departure window is the strongest at 86.1% on time. The 8pm–5am window is the weakest at 53.9%, 32 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 SMF to SAN?
August is the weakest month at 51.4% on time, compared with 80.7% in March. Across the year that is 29 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
- SAN to SMF — the return legseparate record
- Sacramento International (SMF) delay statistics
- San Diego International (SAN) delay statistics
- Alaska Airlines on SMF to SAN84.6%
- SkyWest Airlines on SMF to SAN75.6%
- Southwest Airlines on SMF to SAN67.1%
- SMF to LAX, a related route85.6%
- SFO to SAN, a related route62.2%
- SMF to SEA, a related route83.0%
- Alaska Airlines on-time record84.6%
- SkyWest Airlines on-time record75.6%
- Southwest Airlines on-time record67.1%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. SMF to SAN and SAN to SMF are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.