Route reliability
San Francisco (SFO) to Boston (BOS): which airline is most on time?
On-time arrivals, cancellations and long delays for every airline that reported nonstop flights from San Francisco, CA (SFO) to Boston, MA (BOS), September 2025 to August 2026.
San Francisco, CABoston, MA
Route at a glance · September 2025 to August 2026
SFO to BOS
San Francisco, CA to Boston, MA
- On time
- 73.1%vs 75.6% U.S. average Worse than average
- Cancelled
- 1.8%vs 1.9% U.S. average About average
- 60+ min late
- 10.0%vs 8.1% U.S. average Worse than average
- Scheduled flights
- 4,815in 12 months5 airlines
- Most reliable airline
- United Airlines77.5% on time · 1,939 flights
On time less often than the U.S. average, with a typical cancellation rate.
Airlines on this route
Ranked by on-time arrival
| Airline | On time | Cancelled | 60+ min late | Avg delay when late | Diverted | Flights |
|---|---|---|---|---|---|---|
| 1. Alaska Airlines Small sample (under 300 flights) | 79.7% | 0.8% | 9.8% | 63 min | 0.0% | 123 |
| 2. United Airlines Most reliable | 77.5% | 1.1% | 9.0% | 73 min | 0.2% | 1,939 |
| 3. Delta Air Lines | 70.1% | 1.6% | 9.2% | 69 min | 0.4% | 946 |
| 4. JetBlue Airways | 69.4% | 2.8% | 11.6% | 78 min | 0.1% | 1,806 |
| Southwest Airlines | Insufficient sample (fewer than 50 flights) | 1 | ||||
On time = arrived within 15 minutes of schedule. Avg delay when late = average arrival delay of flights 15+ minutes late. "Most reliable" needs at least 300 flights in 12 months. Tap a heading to sort.
What this means
United Airlines has the strongest record on this route.
- United Airlines had the best on-time record from San Francisco (SFO) to Boston (BOS): 77.5% of its 1,939 scheduled flights arrived within 15 minutes of schedule, compared with 69.4% for JetBlue Airways.
- Alaska Airlines (79.7% on 123 flights) scored higher but flew the route far less often, so that result is less certain.
- Southwest Airlines also flew this route but with fewer than 50 reported flights, too few to rate.
- 1.8% of flights on this route were cancelled (about 1 in 56), about the same as the U.S. average of 1.9%.
- 10.0% of flights, about 1 in 10, arrived an hour or more late. When a flight was late (15+ minutes), the average arrival delay was 74 min.
- Overall, 73.1% of flights on this route arrived on time, 2.5 points lower than the U.S. average of 75.6%.
- Over the last 3 years, November was the most reliable month on this route (82.3% on time) and July the least reliable (71.6%).
- Cancellations peaked in February, when 3.5% of flights were cancelled.
- Flights scheduled to depart 7 am to 8 am were the most punctual (85.7% on time); flights scheduled to depart 11 am to noon were the least (62.7%).
- In the other direction, Boston (BOS) to San Francisco (SFO), 67.9% of flights were on time and 1.6% were cancelled. Compare airlines BOS to SFO.
Best and worst months to fly SFO to BOS
Share of scheduled flights on time 12-month average 73.1%
Show as table
| Period | On time | Flights |
|---|---|---|
| January | 78.2% | 905 |
| February | 79.1% | 828 |
| March | 78.6% | 976 |
| April | 80.1% | 1,073 |
| May | 74.2% | 1,270 |
| June | 74.8% | 1,335 |
| July | 71.6% | 1,402 |
| August | 74.1% | 1,369 |
| September | 73.4% | 1,265 |
| October | 81.1% | 1,295 |
| November | 82.3% | 1,069 |
| December | 77.4% | 1,074 |
| Airline | Best month | Worst month |
|---|---|---|
| Alaska Airlines | November (93.8%) | July (67.5%) |
| United Airlines | October (83.3%) | September (73.5%) |
| Delta Air Lines | December (83.7%) | April (67.7%) |
| JetBlue Airways | April (83.6%) | July (65.6%) |
Month by month, last 12 months
Share of scheduled flights on time U.S. average 75.6%
Show as table
| Period | On time | Flights |
|---|---|---|
| Sep 2025 | 72.1% | 408 |
| Oct 2025 | 70.1% | 428 |
| Nov 2025 | 76.1% | 360 |
| Dec 2025 | 81.2% | 356 |
| Jan 2026 | 77.3% | 313 |
| Feb 2026 | 77.7% | 283 |
| Mar 2026 | 77.7% | 323 |
| Apr 2026 | 76.4% | 381 |
| May 2026 | 75.4% | 439 |
| Jun 2026 | 68.3% | 502 |
| Jul 2026 | 64.6% | 509 |
| Aug 2026 | 69.0% | 513 |
Best and worst departure times
Share of scheduled flights on time
Show as table
| Period | On time | Flights |
|---|---|---|
| Departing 6 am to 7 am | 84.8% | 171 |
| Departing 7 am to 8 am | 85.7% | 614 |
| Departing 8 am to 9 am | 79.0% | 525 |
| Departing 9 am to 10 am | Insufficient sample | 34 |
| Departing 10 am to 11 am | 63.5% | 315 |
| Departing 11 am to noon | 62.7% | 346 |
| Departing noon to 1 pm | 62.8% | 546 |
| Departing 1 pm to 2 pm | 67.6% | 355 |
| Departing 2 pm to 3 pm | 72.3% | 112 |
| Departing 3 pm to 4 pm | 65.8% | 407 |
| Departing 4 pm to 5 pm | 83.9% | 193 |
| Departing 5 pm to 6 pm | Insufficient sample | 1 |
| Departing 8 pm to 9 pm | 79.9% | 154 |
| Departing 9 pm to 10 pm | 74.4% | 453 |
| Departing 10 pm to 11 pm | 76.4% | 174 |
| Departing 11 pm to midnight | 74.2% | 415 |
Sources & data dates
- Source
- U.S. DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (1987-present)
- Period
- September 2025 to August 2026 (12 months); month-of-year patterns September 2023 to August 2026
- Data through
- August 2026
- Processed
- 2026-11-03
- Scope
- Nonstop scheduled flights from San Francisco, CA (SFO) to Boston, MA (BOS), one direction. Airlines that report to the DOT only.
- Method
- Rates use all scheduled flights as the denominator; cancelled and diverted flights count as not on time. Figures based on fewer than 50 scheduled flights are suppressed. Full methodology.