Best Time to Fly BOS to SFO: On-Time Stats by Hour & Airline
Logan International → San Francisco International
Data through July 2026 · Last updated October 18, 2026
4,735 flights were scheduled from Boston (BOS) to San Francisco (SFO) in the last 12 months, and 71.5% of those that flew arrived on time, 6.1 points below the US average of 77.6%.
Among 4 airlines, United Airlines led with 75.3% on time and Alaska Airlines was last with 60.1%.
Over 24 months, Tuesday was the most reliable day (81% on time) and June the worst month (68%).
The cancellation rate was 1.5% (US average 1.8%).
BOS to SFO on-time performance by airline
Last 12 months. Airlines with fewer than 30 completed flights are marked “limited data”.
| Airline | On time | Avg delay when late | Cancelled | Flights |
|---|---|---|---|---|
| United Airlines | 75.3% | 67 min | 1.3% | 1,905 |
| Delta Air Lines | 71.4% | 63 min | 1.5% | 918 |
| JetBlue | 68.6% | 67 min | 1.8% | 1,738 |
| Alaska Airlines | 60.1% | 69 min | 0.6% | 173 |
| Southwest Airlines | Limited data | 1 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly BOS to SFO
On-time arrival % by scheduled departure hour (local time), 9,323 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 5am–6am | 83.2% | 0.0% | 95 |
| 6am–7am | 87.6% | 0.4% | 982 |
| 7am–8am | 81.9% | 1.3% | 1,243 |
| 8am–9am | 85.7% | 0.7% | 755 |
| 9am–10am | 75.5% | 0.3% | 311 |
| 10am–11am | 81.4% | 0.9% | 565 |
| 11am–12pm | 80.0% | 0.6% | 545 |
| 12pm–1pm | 78.1% | 0.0% | 65 |
| 1pm–2pm | 81.8% | 0.4% | 502 |
| 2pm–3pm | 82.2% | 0.0% | 191 |
| 3pm–4pm | 74.9% | 1.9% | 373 |
| 4pm–5pm | 60.4% | 1.0% | 505 |
| 5pm–6pm | 69.0% | 1.2% | 891 |
| 6pm–7pm | 64.1% | 0.8% | 891 |
| 7pm–8pm | 61.0% | 0.9% | 338 |
| 8pm–9pm | 63.0% | 1.6% | 886 |
| 9pm–10pm | 63.2% | 0.0% | 185 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on BOS to SFO
On-time arrivals during holiday periods compared with all other days, last 24 months.
| Period | On time | vs other days | Cancelled | Flights |
|---|---|---|---|---|
| Thanksgiving week (Tue before to Mon after) | 84.1% | +6.4 pts | 1.2% | 173 |
| Christmas & New Year (Dec 20 - Jan 3) | 57.9% | -19.9 pts | 0.9% | 343 |
| Summer peak (Jun 15 - Aug 15) | 67.9% | -9.8 pts | 1.3% | 1,892 |
| All other days | 77.8% | — | 0.8% | 6,915 |
Monthly on-time trend
On-time arrival % each month, with the 12-month US average for reference.
What causes delays on this route
Share of reported delay minutes, last 12 months (BTS cause categories).