73% of flights from Boston to San Diego arrived on time over the past 12 months. That is worse than the typical U.S. route. The 9 a.m. departures ran on time 87% of the time; the 5 p.m. ones 65%. Most reliable airline: JetBlue (80%). 11% 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 BOS → SAN: when a flight was late, it was under 45 minutes late 56% of the time. About 1 in 12 flights landed an hour or more late, and 1 in 118 three hours or more; 1.8% were cancelled outright.
- On time or early73%
- 15–30 min late9.0%
- 30–60 min late6.9%
- 1–2 hours late5.6%
- 2–3 hours late1.6%
- 3+ hours late0.9%
- Diverted0.7%
- Cancelled1.8%
Share of all 1,880 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 |
|---|---|---|---|---|---|---|---|
| JetBlue | 919 | 80% | 2.0% | −12 min | 7.2% | +69 min | JetBlue |
| Alaska Airlines | 508 | 73% | 1.6% | −5 min | 7.7% | +71 min | Alaska Airlines |
| Delta Air Lines | 364 | 64% | 1.7% | +1 min | 7.4% | +44 min | Delta Air Lines |
| Southwest Airlines | 89 | — | — | — | — | — | 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 BOS). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | JetBlue | Alaska Airlines | Delta Air Lines |
|---|---|---|---|
| 6 a.m. | 87% | — | — |
| 8 a.m. | — | 86% | — |
| 10 a.m. | 84% | — | — |
| 3 p.m. | 77% | — | — |
| 4 p.m. | 72% | 73% | — |
| 5 p.m. | — | 71% | 64% |
Last flight of the day
On BOS → SAN, each airline's last flight of the day was cancelled 1.4% of the time, against 2.3% for its earlier flights, so here the last flight is actually the safer one. It arrived 3+ hours late 0.8% of the time (earlier flights: 0.9%). 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 | 4:33 p.m. | 0.7% | 1.3% | 2.6% | first flight 8:28 a.m. |
| JetBlue | 4:20 p.m. | 1.7% | 0.6% | 2.2% | first flight 6:05 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: March (84%). Worst: February (71%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 289 | 73% | 3.5% |
| Tuesday | 267 | 75% | 3.0% |
| Wednesday | 264 | 72% | 1.5% |
| Thursday | 277 | 74% | 1.1% |
| Friday | 283 | 71% | 1.1% |
| Saturday | 217 | 76% | 0.5% |
| Sunday | 283 | 74% | 1.8% |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: weather 17 · airline 13 · air traffic/airport 4
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 |
|---|---|---|---|---|---|---|
| B6 619 | 6:05 a.m. | 263 | 85% | 1.9% | −16 min | JetBlue |
| B6 219 | 8:50 a.m. | 154 | 80% | 3.3% | −13 min | JetBlue |
| B6 319 | 4:20 p.m. | 158 | 73% | 0.6% | −5 min | JetBlue |
| AS 389 | 4:33 p.m. | 314 | 68% | 1.3% | −3 min | Alaska Airlines |
| DL 571 | 5:10 p.m. | 364 | 64% | 1.7% | +1 min | Delta Air Lines |
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Feb 23, 2026 | 4 | 0% | 4 |
| Dec 3, 2025 | 4 | 0% | 0 |
| Feb 17, 2026 | 4 | 0% | 0 |
| Feb 11, 2026 | 4 | 0% | 0 |
| Jan 26, 2026 | 4 | 0% | 4 |
Questions
How often are flights from BOS to SAN on time?
73% of 1,880 scheduled flights from Boston, MA to San Diego, CA arrived within 15 minutes of schedule between September 2025 and August 2026. 1.8% were cancelled.
What is the best time of day to fly BOS to SAN?
Flights scheduled to leave at 9 a.m. were the most reliable (87% on time). The 5 p.m. departures were the least (65%).
Which airline is most on time from BOS to SAN?
JetBlue: 80% of its 919 flights on the route arrived on time. Alaska Airlines: 73%. Delta Air Lines: 64%.
What month has the most delays from BOS to SAN?
February (71% on time). The best month is March (84%), over 2023–2026.
Is the last flight of the day from BOS to SAN more likely to be cancelled?
No, the opposite. Each airline's last BOS–SAN flight of the day was cancelled 1.4% of the time over the past year, against 2.3% for its earlier flights. If the last flight is cancelled, the next one is usually the following morning.
Related
- SAN → BOS (return)
- Boston Logan (BOS) delays by hour
- Flights into San Diego (SAN)
- JetBlue on-time record
- Alaska Airlines on-time record
- Delta Air Lines 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.