Best Time to Fly SFO to BOS: On-Time Stats by Hour & Airline
San Francisco International → Logan International
Data through July 2026 · Last updated October 18, 2026
4,733 flights were scheduled from San Francisco (SFO) to Boston (BOS) in the last 12 months, and 76.0% of those that flew arrived on time, 1.7 points below the US average of 77.6%.
Among 4 airlines, United Airlines led with 79.5% on time and Delta Air Lines was last with 73.1%.
Over 24 months, Saturday was the most reliable day (84% on time) and July the worst month (71%).
The cancellation rate was 1.7% (US average 1.8%).
SFO to BOS 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 | 79.5% | 73 min | 1.2% | 1,904 |
| Alaska Airlines | 78.5% | 63 min | 0.6% | 173 |
| JetBlue | 73.4% | 81 min | 2.4% | 1,736 |
| Delta Air Lines | 73.1% | 72 min | 1.5% | 919 |
| Southwest Airlines | Limited data | 1 | ||
80%+ good 70–79.9% fair <70% poor
Best time of day to fly SFO to BOS
On-time arrival % by scheduled departure hour (local time), 9,319 flights over 24 months.
Show the numbers
| Departure hour | On time | Cancelled | Flights |
|---|---|---|---|
| 6am–7am | 87.8% | 1.2% | 340 |
| 7am–8am | 88.8% | 0.8% | 1,475 |
| 8am–9am | 83.5% | 0.8% | 974 |
| 9am–10am | 68.1% | 0.0% | 95 |
| 10am–11am | 69.9% | 0.2% | 626 |
| 11am–12pm | 68.5% | 0.7% | 676 |
| 12pm–1pm | 69.9% | 2.1% | 619 |
| 1pm–2pm | 73.3% | 1.1% | 980 |
| 2pm–3pm | 77.7% | 0.4% | 225 |
| 3pm–4pm | 75.9% | 1.5% | 667 |
| 4pm–5pm | 86.2% | 1.6% | 184 |
| 5pm–6pm | Limited data | 1 | |
| 8pm–9pm | 82.7% | 1.1% | 370 |
| 9pm–10pm | 75.6% | 1.0% | 895 |
| 10pm–11pm | 78.2% | 0.7% | 291 |
| 11pm–12am | 79.7% | 0.9% | 901 |
Best day of the week
24 months, by day of departure.
Best month to fly
24 months, by calendar month.
Holiday travel on SFO to BOS
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) | 87.5% | +7.5 pts | 1.8% | 171 |
| Christmas & New Year (Dec 20 - Jan 3) | 72.4% | -7.6 pts | 0.3% | 343 |
| Summer peak (Jun 15 - Aug 15) | 72.8% | -7.2 pts | 1.4% | 1,892 |
| All other days | 80.0% | — | 0.9% | 6,913 |
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).