Route reliability record
OAK→SAN
Oakland to San Diego
- Flights
- 3,201
- Period
- July 2025 to June 2026
- Distance
- 446 mi
- Carriers
- 3
This route draws a C+. About one flight in three arrive at least 15 minutes late, and the typical late arrival is about 50 minutes behind schedule. Build slack into anything you connect to. That rests on 3,201 flights, with a median arrival 3 minutes late.
The national on-time rate over the same period is 77.6%, so this route runs 11 points behind the country as a whole. Across a thousand flights that is about 107 extra late arrivals.
Key figures
On time
66.9%
Arrivals under 15 minutes late, of 3,167 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
0.97%
National rate is 1.81%
Best carrier
Southwest
66.6% on time across 2,939 flights
These figures cover 3,201 flights between July 2025 and June 2026. Beyond the headline rate, 8.8% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.
Carrier by carrier
Which airline is most reliable on OAK to SAN
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 |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 55 | 78.2% | 63 min | 0.00% | B+ |
| SkyWest Airlinesthin sample | 207 | 68.6% | 51 min | 1.45% | C |
| Southwest Airlines | 2,939 | 66.6% | 49 min | 0.95% | C+ |
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 45 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–8am569 flights91.8%
- 8am–11am671 flights74.3%
- 11am–2pm504 flights68.6%
- 2pm–5pm677 flights59.2%
- 5pm–8pm479 flights47.3%
- 8pm–5am301 flights49.7%
Scale runs 40% to 95%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 47.3% on time, against 91.8% 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 677 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 19 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.
December is the weak month at 58.4% on time, against 77.2% in January. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 339 flights.
Across the week, Saturday is the strongest day at 77.6% on time and Thursday the weakest at 58.0%. 20 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 44% of the 52,000 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.
- 44%Late-arriving aircraft
- 29%National Airspace System
- 26%Carrier
- 1%Extreme weather
- 0%Security
44% 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 52,000 reported delay minutes here, that single category outweighs weather by 43 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 51,992 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 91.8% on time here.
Cancellations sit at 0.97% against a national 1.81%, which is ordinary. Diversions add another 0.09%.
Connections and stage length
What a delay here actually costs
8.8% 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 about 50 minutes kind, which a normal layover absorbs.
At 446 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 3,195 flights, 8 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 8 points of difference.
The sample behind these figures is 3,201 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. January runs 77.2% on time and December 58.4%, a swing of 19 points. If the dates move at all, move them out of December before you think about anything else. 3,167 completed flights over 12 months sit behind that.
Common questions
OAK to SAN questions
How often is OAK to SAN delayed?
About one flight in three arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 33.1% of the 3,201 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 50 minutes on average.
How reliable is OAK to SAN compared with the rest of the country?
66.9% of flights arrive on time here against a national 77.6%, a difference of 11 points against it. That is worth a C+ on this site's grading scale.
What time of day has the fewest delays on OAK to SAN?
The 5am–8am departure window is the strongest at 91.8% on time. The 5pm–8pm window is the weakest at 47.3%, 45 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 December delays on OAK to SAN?
December is the weakest month at 58.4% on time, compared with 77.2% in January. Across the year that is 19 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 OAK — the return legseparate record
- Oakland International (OAK) delay statistics
- San Diego International (SAN) delay statistics
- Spirit Airlines on-time record78.2%
- SkyWest Airlines on-time record68.6%
- Southwest Airlines on-time record66.6%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. OAK to SAN and SAN to OAK 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.