68% of flights from Santa Rosa to San Diego arrived on time over the past 12 months. That is worse than the typical U.S. route. The 6 a.m. departures ran on time 85% of the time; the 5 p.m. ones 38%. Most reliable airline: Southwest Airlines (74%). 12% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for STS → SAN: when a flight was late, it was under 45 minutes late 57% of the time. About 1 in 13 flights landed an hour or more late, and 1 in 90 three hours or more; 4.1% were cancelled outright.
- On time or early68%
- 15–30 min late9.7%
- 30–60 min late10%
- 1–2 hours late4.5%
- 2–3 hours late1.9%
- 3+ hours late1.1%
- Diverted0.2%
- Cancelled4.1%
Share of all 1,166 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| Alaska Airlines | 936 | 67% | 5.0% | −1 min | 8.0% | +59 min | SkyWest 89%, Horizon Air 11% |
| Southwest Airlines | 230 | 74% | 0.4% | −5 min | 5.7% | +60 min | Southwest Airlines |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at STS). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | Alaska Airlines | Southwest Airlines |
|---|---|---|
| 6 a.m. | 78% | 93% |
| 10 a.m. | 66% | — |
| 7 p.m. | 58% | — |
Last flight of the day
On STS → SAN, each airline's last flight of the day was cancelled 1.9% of the time, against 5.8% for its earlier flights, so here the last flight is actually the safer one. It arrived 3+ hours late 1.0% of the time (earlier flights: 1.2%). It matters more than the numbers suggest. Miss an earlier flight and there's another one that evening; miss the last one and you're usually waiting until morning.
| Airline | Last departure | Last: cancelled | Last: 3h+ late | Earlier: cancelled | Next morning |
|---|---|---|---|---|---|
| Alaska Airlines | 5:56 p.m. | 2.4% | 0.6% | 6.5% | first flight 6:26 a.m. |
Last flight = the airline's last scheduled departure on this route that day, on days it flies the route at least twice; past 12 months. Times are typical scheduled times over the latest three months.
By month
Each calendar month pooled over 2023–2026. Best: October (77%). Worst: December (61%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 189 | 66% | 2.6% |
| Tuesday | 141 | 77% | 6.4% |
| Wednesday | 146 | 79% | 4.1% |
| Thursday | 182 | 60% | 2.8% |
| Friday | 186 | 61% | 3.8% |
| Saturday | 139 | 78% | 5.0% |
| Sunday | 183 | 64% | 4.9% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 29 · air traffic/airport 11 · airline 8
Month by month
Flight numbers on this route
Regular flights with at least 120 scheduled trips in the past year. Sorted by departure time.
| Flight | Departs | Flights | On time | Cancelled | Typical arrival | Operated by |
|---|---|---|---|---|---|---|
| AS 3315 | 6:26 a.m. | 303 | 81% | 7.9% | −10 min | SkyWest |
| AS 3047 | 11:04 a.m. | 203 | 54% | 1.0% | +12 min | SkyWest |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Aug 23, 2026 | 5 | 0% | 0 |
| Dec 30, 2025 | 3 | 0% | 1 |
| Sep 18, 2025 | 3 | 0% | 0 |
| Dec 19, 2025 | 3 | 0% | 1 |
| Aug 9, 2026 | 5 | 20% | 1 |
Questions
How often are flights from STS to SAN on time?
68% of 1,166 scheduled flights from Santa Rosa, CA to San Diego, CA arrived within 15 minutes of schedule between September 2025 and August 2026. 4.1% were cancelled.
What is the best time of day to fly STS to SAN?
Flights scheduled to leave at 6 a.m. were the most reliable (85% on time). The 5 p.m. departures were the least (38%).
Which airline is most on time from STS to SAN?
Southwest Airlines: 74% of its 230 flights on the route arrived on time. Alaska Airlines: 67%.
What month has the most delays from STS to SAN?
December (61% on time). The best month is October (77%), over 2023–2026.
Is the last flight of the day from STS to SAN more likely to be cancelled?
No, the opposite. Each airline's last STS–SAN flight of the day was cancelled 1.9% of the time over the past year, against 5.8% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- SAN → STS (return)
- Charles M. Schulz Sonoma (STS) delays by hour
- Flights into San Diego (SAN)
- Alaska Airlines on-time record
- Southwest Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.