Route reliability record
SAN→STS
San Diego to Santa Rosa
- Flights
- 960
- Period
- July 2025 to June 2026
- Distance
- 508 mi
- Carriers
- 2
This route lands a B−, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 45 minutes on average. That is a workable record, not a spotless one. That rests on 960 SAN to STS flights, with a median arrival 8 minutes early.
Best time to fly SAN to STS: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 86.7% of the time and Wednesday flights 88.2%, against 78.8% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.8%
Arrivals under 15 minutes late, of 925 completed flights
Avg delay
47 min
Across delayed arrivals only, not all flights
Cancelled
3.02%
National rate is 1.81%
Best carrier
SkyWest
80.3% on time across 827 flights
These figures cover 960 flights between July 2025 and June 2026. The median arrival is 8 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on SAN to STS
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 |
|---|---|---|---|---|---|
| SkyWest Airlines | 827 | 80.3% | 48 min | 3.39% | B− |
| Southwest Airlinesthin sample | 133 | 69.7% | 45 min | 0.75% | C+ |
Flight by flight
Flights on SAN to STS
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.
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 16 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–8am45 flights86.7%
- 8am–11am282 flights84.4%
- 11am–2pm171 flights72.8%
- 2pm–5pm31 flights71.0%
- 5pm–8pm66 flights84.6%
- 8pm–5am365 flights75.9%
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.7% of the time, against 71.0% for the afternoon window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 8pm–5am window is the busiest, with 365 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 26 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 59.6% on time, against 85.3% in March. 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 125 flights.
Across the week, Wednesday is the strongest day at 88.2% on time and Friday the weakest at 66.0%. 22 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 50% of the 9,299 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.
- 50%Late-arriving aircraft
- 26%National Airspace System
- 21%Carrier
- 3%Extreme weather
50% 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 9,299 reported delay minutes here, that single category outweighs weather by 15 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 9,299 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 86.7% on time here.
Cancellations run at 3.02%, against 1.81% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
Connections and stage length
What a delay here actually costs
5.2% 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 last roughly 45 minutes, which a normal layover absorbs.
The 508 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.
The return leg runs 76.1% on time across 959 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
One caution: this is a thin sample. 960 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
Work out the risk of missing a connection in STS after this flight
What to do with this
Booking this route
Put together: the delay figures matter less here than the 3.02% cancellation rate. A late arrival costs you roughly 45 minutes; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 925 completed flights over 12 months sit behind that.
Common questions
SAN to STS questions
How often is SAN to STS delayed?
About one flight in five arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.2% of the 960 flights in this analysis, against 22.4% nationally. Delayed flights are late by roughly 45 minutes on average.
How reliable is SAN to STS compared with the rest of the country?
78.8% of flights arrive on time here against a national 77.6%, a difference of about a point in its favour. That is worth a B− on this site's grading scale.
What time of day has the fewest delays on SAN to STS?
The 5am–8am departure window is the strongest at 86.7% on time. The 2pm–5pm window is the weakest at 71.0%, 16 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 SAN to STS?
December is the weakest month at 59.6% on time, compared with 85.3% in March. Across the year that is 26 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
- STS to SAN — the return legseparate record
- San Diego International (SAN) delay statistics
- SkyWest Airlines on SAN to STS80.3%
- Southwest Airlines on SAN to STS69.7%
- SAN to SFO, a related route65.0%
- SNA to STS, a related route78.8%
- SAN to DEN, a related route79.2%
- SkyWest Airlines on-time record80.3%
- Southwest Airlines on-time record69.7%
- The US routes with the most cancellations
- Why the first flight of the morning is statistically safest
Direction matters. SAN to STS and STS to SAN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed SAN to STS’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.