Boston (BOS) to San Francisco (SFO): On-Time Performance
Data through July 2026
The calendar drives reliability on BOS–SFO. January 2025 flights landed on schedule 88% of the time, but June 2026 dropped to 56% — a gap of 32 points. Across the full period the route averages 75% on-time against a national 78%. Morning departures also hold up better than evening ones (83% vs 64%), which matters most in the rough months.
- On-time
- 75%
- arrived <15 min late
- Avg delay
- 17 min
- completed flights
- Cancelled
- 1.0%
- Flights/day
- 13
- last 12 months
- Duration
- 6h 43m
- scheduled
- Distance
- 2,704 mi
Best airline from BOS to SFO
4 airlines flew this route regularly between 2024-07 and 2026-07.
| Airline | On-time | Avg delay | Cancelled | Flights |
|---|---|---|---|---|
| United Airlinesmost reliable | 79% | 14 min | 1.0% | 3,817 |
| JetBlue Airways | 73% | 18 min | 1.1% | 3,496 |
| Delta Air Lines | 73% | 18 min | 1.2% | 1,834 |
| Alaska Airlines | 69% | 21 min | 0.2% | 618 |
Monthly on-time trend
Best time to fly from BOS to SFO
Aim for departures around 6 a.m. (88% on-time); avoid 9 p.m. departures (57%).
By day of week
| Day | On-time | Avg delay |
|---|---|---|
| Monday | 73% | 18 min |
| Tuesdaybest | 82% | 13 min |
| Wednesday | 79% | 15 min |
| Thursday | 72% | 19 min |
| Friday | 74% | 18 min |
| Saturday | 77% | 14 min |
| Sunday | 71% | 20 min |
What causes delays on this route
Share of total delay minutes by cause, as reported by carriers to the US DOT.
- Late-arriving aircraft35%
- Airline operations27%
- National airspace system36%
- Weather3%
Frequently asked questions
- How often are flights from BOS to SFO delayed?
- 25% of BOS–SFO flights arrived 15 or more minutes late (the US DOT definition of a delay) between 2024-07 and 2026-07. The average arrival delay across completed flights was 17 minutes.
- Which airline is most reliable from BOS to SFO?
- United Airlines has the best on-time record on this route at 79%, based on 3,817 flights. 4 airlines flew BOS–SFO frequently enough to compare in this period.
- What is the best time of day to fly from BOS to SFO?
- Departures around 6 a.m. have the best record (88% on-time), while departures around 9 p.m. have the worst (57%). As on most US routes, delays accumulate through the day, so earlier flights are generally safer.
- How long is the flight from BOS to SFO?
- The scheduled BOS–SFO flight time averages 6h 43m over 2,704 miles. Actual arrival times vary — flights on this route land 15+ minutes late 25% of the time.
- How often are BOS to SFO flights cancelled?
- 1% of scheduled flights on this route were cancelled between 2024-07 and 2026-07, at or below the national rate of 1.6%.
- What is the worst month to fly from BOS to SFO?
- June 2026 was the roughest month in this dataset, with only 56% of arrivals on time. The best was January 2025 at 88%. If your dates are flexible, that 32-point gap is worth planning around.
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Based on 9,766 flights, 2024-07–2026-07. Source: US DOT Bureau of Transportation Statistics. Updated 2026-09-28.