Route reliability record

SMF→SAN

Sacramento to San Diego

Flights: 5,182
Period: July 2025 to June 2026
Distance: 480 mi
Carriers: 3

This route sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land roughly 50 minutes behind schedule. That rests on 5,182 flights, of which SkyWest Airlines flew 1,187 at 79.0% on time.

The national on-time rate over the same period is 77.6%, so this route runs 4 points behind the country as a whole. Across a thousand flights that is about 43 extra late arrivals.

On time

73.3%

Arrivals under 15 minutes late, of 5,120 completed flights

Avg delay

49 min

Across delayed arrivals only, not all flights

Cancelled

0.93%

National rate is 1.81%

Best carrier

SkyWest

79.0% on time across 1,187 flights

These figures cover 5,182 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

Which airline is most reliable on SMF to SAN

The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 79.0% of the time; Southwest Airlines manages 70.9%. Sample sizes sit next to every figure, because a two-point gap across 3,810 flights means less than a ten-point one.

On-time performance by carrier on SMF to SAN
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	3,810	70.9%	48 min	0.55%	C+

SkyWest leads Southwest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

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 27 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am949 flights87.6%
8am–11am903 flights83.6%
11am–2pm899 flights73.8%
2pm–5pm1,057 flights65.4%
5pm–8pm1,032 flights62.8%
8pm–5am342 flights60.2%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 60.2% on time, against 87.6% 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 1,057 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 18 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.

Darker means more delays. Figures are on-time percentages.March best, June worst

June is the worst month at 62.6% on time, 18 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, Tuesday is the strongest day at 83.0% on time and Friday the weakest at 64.7%. 18 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 67,000 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.

Late-arriving aircraft
46%
National Airspace System
29%
Carrier
23%
Extreme weather
2%
Security
0%

46% 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 67,000 reported delay minutes here, that single category outweighs weather by 30 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 66,898 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 87.6% on time here.

Cancellations sit at 0.93% against a national 1.81%, which is ordinary. Diversions add another 0.27%.

Connections and stage length

What a delay here actually costs

6.2% 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 are the roughly 50 minutes kind, 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 76.4% on time across 5,177 flights, 3 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 3 points of difference.

The sample behind these figures is 5,182 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 this route

Put together: the calendar is the biggest lever here, not the carrier or the hour. March runs 80.7% on time and June 62.6%, a swing of 18 points. If the dates move at all, move them out of June before you think about anything else. 5,120 completed flights over 12 months sit behind that.

Common questions

SMF to SAN questions

How often is SMF to SAN delayed?

About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.7% of the 5,182 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 50 minutes on average.

Which airline is most reliable on SMF to SAN?

SkyWest Airlines leads at 79.0% on time across 1,187 flights. Southwest Airlines is at the other end on 70.9%, a gap of 8 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 87.6% on time. The 8pm–5am window is the weakest at 60.2%, 27 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 June delays on SMF to SAN?

June is the weakest month at 62.6% on time, compared with 80.7% in March. Across the year that is 18 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

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.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures