Route reliability record
SJC→SAN
San Jose to San Diego
- Flights
- 5,004
- Period
- September 2025 to August 2026
- Distance
- 417 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, 9 points worse than the national rate of 77.3%. The late ones land roughly 45 minutes behind schedule. That rests on 5,004 SJC to SAN flights, of which SkyWest Airlines flew 1,148 at 73.0% on time.
Best time to fly SJC to SAN: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 89.2% of the time and Tuesday flights 81.1%, against 68.3% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 9 points behind the country as a whole. Across a thousand flights that is about 90 extra late arrivals.
Key figures
On time
68.3%
Arrivals under 15 minutes late, of 4,941 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
1.06%
National rate is 1.89%
Best carrier
SkyWest
73.0% on time across 1,148 flights
These figures cover 5,004 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 SJC to SAN
The choice of carrier is not cosmetic here. SkyWest Airlines arrives on time 73.0% of the time; Southwest Airlines manages 66.5%. Sample sizes sit next to every figure, because a two-point gap across 3,745 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Alaska Airlinesthin sample | 111 | 83.6% | 43 min | 0.90% | B+ |
| SkyWest Airlines | 1,148 | 73.0% | 50 min | 1.39% | C |
| Southwest Airlines | 3,745 | 66.5% | 46 min | 0.96% | C+ |
SkyWest leads Southwest by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on SJC to SAN
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly San Jose to San Diego
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 3 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. SFO → SANSan Francisco to San Diego | United Airlines | 72.6% | 72.8% | 0.34% | 5am–8am, Sat | UA 2177 10:05 |
| 2. SJC → SANSan Jose to San Diego | SkyWest Airlines | 72.0% | 73.0% | 1.39% | 5am–8am, Sat | OO 3499 09:09 |
| 3. SJC → SANSan Jose to San Diego | Southwest Airlines | 65.9% | 66.5% | 0.96% | 5am–8am, Tue | — |
| 4. OAK → SANOakland to San Diego | Southwest Airlines | 61.9% | 62.5% | 0.93% | 5am–8am, Sat | — |
| 5. SFO → SANSan Francisco to San Diego | SkyWest Airlines | 58.7% | 60.1% | 2.36% | 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 33 points, against 7 points between the best and worst carrier.
- 5am–8am764 flights89.2%
- 8am–11am1,212 flights74.9%
- 11am–2pm826 flights66.9%
- 2pm–5pm806 flights60.8%
- 5pm–8pm1,019 flights56.1%
- 8pm–5am377 flights57.1%
Scale runs 50% to 95%.
The 5pm–8pm window is where this operation falls apart: 56.1% on time, against 89.2% 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 8am–11am window is the busiest, with 1,212 flights scheduled in it.
Explore
Filter SJC 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 SJC to SAN, the best departure window is 5am–8am at 89.2% on time and the worst is 5pm–8pm at 56.1%, a wide gap of 33.1 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am89.2%
- 8–11am74.9%
- 11am–2pm66.9%
- 2–5pm60.8%
- 5–8pm56.1%
- 8pm–5am57.1%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 35 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 46.8% on time, 35 points below January, the best at 81.4%. 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 478 flights.
Across the week, Tuesday is the strongest day at 81.1% on time and Friday the weakest at 57.7%, a spread of 23 points.
Delay causes
Why this route gets delayed
National Airspace System accounts for 43% of the 73,000 delay minutes carriers reported here, and the remaining four split what is left.
- 43%National Airspace System
- 38%Late-arriving aircraft
- 18%Carrier
- 1%Extreme weather
- 0%Security
38% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 73,000 reported delay minutes here, that single category outweighs weather by 38 to one. The split is drawn from 72,699 reported delay minutes.
43% 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 31,000 minutes out of 73,000, against a national NAS share of 21%.
Cancellations sit at 1.06% against a national 1.89%, which is ordinary. Diversions add another 0.20%.
Connections and stage length
What a delay here actually costs
7.2% 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 roughly 45 minutes, which a normal layover absorbs.
At 417 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 4,973 flights, 6 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 6 points of difference.
The sample behind these figures is 5,004 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. January runs 81.4% on time and August 46.8%, a swing of 35 points. If the dates move at all, move them out of August before you think about anything else. 4,941 completed flights over 12 months sit behind that.
Common questions
SJC to SAN questions
How often is SJC to SAN delayed?
About 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 31.7% of the 5,004 flights in this analysis, against 22.7% nationally. Delayed flights are late by roughly 45 minutes on average.
Which airline is most reliable on SJC to SAN?
SkyWest Airlines leads at 73.0% on time across 1,148 flights. Southwest Airlines is at the other end on 66.5%, a gap of 7 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 SJC to SAN?
The 5am–8am departure window is the strongest at 89.2% on time. The 5pm–8pm window is the weakest at 56.1%, 33 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 SJC to SAN?
August is the weakest month at 46.8% on time, compared with 81.4% in January. Across the year that is 35 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 SJC — the return legseparate record
- Norman Y. Mineta San Jose International (SJC) delay statistics
- San Diego International (SAN) delay statistics
- Alaska Airlines on SJC to SAN83.6%
- SkyWest Airlines on SJC to SAN73.0%
- Southwest Airlines on SJC to SAN66.5%
- SJC to LAX, a related route85.0%
- SFO to SAN, a related route62.2%
- SJC to SEA, a related route82.7%
- Alaska Airlines on-time record83.6%
- SkyWest Airlines on-time record73.0%
- Southwest Airlines on-time record66.5%
- 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. SJC to SAN and SAN to SJC 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.