Route reliability record
SAN→STS
San Diego to Santa Rosa
- Flights
- 1,064
- Period
- September 2025 to August 2026
- Distance
- 508 mi
- Carriers
- 2
This route carries a cancellation problem, not just a delay problem: 3.5% of scheduled flights never operate, against 1.9% nationally. Of the ones that do fly, close to three flights in four arrive on time, worth a B− overall. The punctuality figure counts only flights that actually departed, so it flatters an operation that cancels this often. That rests on 1,064 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 90.9% of the time and Wednesday flights 87.4%, against 77.5% for the route overall.
The US average over the same twelve months is 77.3%, 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
77.5%
Arrivals under 15 minutes late, of 1,019 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
3.48%
National rate is 1.89%
Best carrier
SkyWest
80.1% on time across 833 flights
These figures cover 1,064 flights between September 2025 and August 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.
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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 | 833 | 80.1% | 51 min | 4.08% | B− |
| Southwest Airlinesthin sample | 231 | 68.7% | 47 min | 1.30% | 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.
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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 22 points, against half a point between the best and worst carrier.
- 5am–8am33 flights90.9%
- 8am–11am330 flights87.0%
- 11am–2pm172 flights72.9%
- 2pm–5pm36 flights69.4%
- 5pm–8pm78 flights85.7%
- 8pm–5am415 flights69.5%
Scale runs 60% to 95%.
Book the early departure. Flights leaving between 5am–8am arrive on time 90.9% of the time, against 69.4% for the afternoon window. That is 22 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 415 flights scheduled in it.
Explore
Filter SAN to STS 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 SAN to STS, the best departure window is 5am–8am at 90.9% on time and the worst is 2pm–5pm at 69.4%, a wide gap of 21.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am90.9%
- 8–11am87.0%
- 11am–2pm72.9%
- 2–5pm69.4%
- 5–8pm85.7%
- 8pm–5am69.5%
best all US flightsScale 60% to 95%.
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 87.4% on time and Friday the weakest at 69.4%, a spread of 18 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 56% of the 11,000 delay minutes carriers reported here, and the remaining four split what is left.
- 56%Late-arriving aircraft
- 24%National Airspace System
- 17%Carrier
- 3%Extreme weather
56% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 11,000 reported delay minutes here, that single category outweighs weather by 21 to one. The split is drawn from 11,363 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 90.9% on time here.
Cancellations run at 3.48%, against 1.89% nationally. That is about 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
6.5% 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 about 50 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.
The return leg is a different operation and performs like one: it runs 73.3% on time across 1,060 flights, 4 points below 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 4 points of difference.
One caution: this is a thin sample. 1,064 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 3.48% cancellation rate. A late arrival costs you about 50 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. 1,019 completed flights over 12 months sit behind that.
Common questions
SAN to STS questions
How often is SAN to STS delayed?
Roughly one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 22.5% of the 1,064 flights in this analysis, against 22.7% nationally. Delayed flights are late by about 50 minutes on average.
How reliable is SAN to STS compared with the rest of the country?
77.5% of flights arrive on time here against a national 77.3%, a difference of half 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 90.9% on time. The 2pm–5pm window is the weakest at 69.4%, 22 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 STS80.1%
- Southwest Airlines on SAN to STS68.7%
- SAN to SFO, a related route59.5%
- SNA to STS, a related route80.5%
- SAN to DEN, a related route78.4%
- SkyWest Airlines on-time record80.1%
- Southwest Airlines on-time record68.7%
- 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.
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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.