BOS to SFO flight delays & on-time performance
Nonstop flights from Boston Logan International Airport to San Francisco International Airport · 2,704 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at BOS or SFO right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from Boston (BOS) to San Francisco (SFO) arrived on time 72% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 1.5% were cancelled, and 10% arrived an hour or more late.
- United Airlines was the most punctual airline here (75% on time); JetBlue was the least (69%).
- Departures scheduled around 8am did best (87% on time); around 7pm did worst (45%).
- Saturday was the most reliable day to fly (77% on time) and Thursday the least (66%).
- The largest source of delay minutes was air traffic control & airport congestion (40%).
Which airline is most on time from BOS to SFO?
Ranked by on-time arrival rate. Regional airlines fly under their partner's brand (e.g. SkyWest for Delta Connection or United Express).
| Airline | On time | Cancelled | Avg delay | 1 hr+ late | Flights |
|---|---|---|---|---|---|
| Southwest Airlines | 100% | 0.0% | 7 min | 0.0% | 1 |
| United Airlines | 75% | 1.3% | 18 min | 9.0% | 1,905 |
| Delta Air Lines | 71% | 1.5% | 20 min | 8.3% | 918 |
| JetBlue | 69% | 1.8% | 22 min | 11.7% | 1,738 |
| Alaska Airlines | 60% | 0.6% | 29 min | 16.1% | 173 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 5am88%52 flights
- 6am85%458 flights
- 7am82%726 flights
- 8am87%256 flights
- 9am69%200 flights
- 10am79%331 flights
- 11am72%288 flights
- 1pm85%185 flights
- 2pm82%99 flights
- 3pm67%194 flights
- 4pm56%356 flights
- 5pm65%409 flights
- 6pm57%368 flights
- 7pm45%145 flights
- 8pm61%575 flights
- 9pm75%73 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday68%3.6% cancelled
- Tuesday76%1.7% cancelled
- Wednesday75%0.9% cancelled
- Thursday66%0.8% cancelled
- Friday70%0.7% cancelled
- Saturday77%0.7% cancelled
- Sunday71%1.8% cancelled
On-time trend by month
Why flights are late
Share of delay minutes by cause, as reported by airlines to the DOT.
- Air traffic control & airport congestion40%
- Late-arriving aircraft35%
- Airline (crew, maintenance, cleaning, fueling)22%
- Extreme weather3%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather55%
- Airline (crew, maintenance, cleaning, fueling)24%
- Air traffic control & airport congestion21%
- Security0%
BOS to SFO: common questions
- How often are BOS to SFO flights on time?
- 72% of flights arrived less than 15 minutes late in Aug 2025 – Jul 2026, compared with 78% for all US flights.
- How often are flights from Boston to San Francisco cancelled?
- 1.5% of scheduled flights were cancelled (71 of 4,735).
- How long are typical delays?
- Across all flights the average arrival delay was 20 min (early arrivals count as zero). Flights that were late arrived 67 min behind schedule on average, and 10.1% of flights were an hour or more late.
- How long is taxi time at BOS?
- Flights on this route spent 22 min taxiing from the gate to takeoff on average.
Related routes
Return trip: SFO to BOS — 76% on time
More flights from Boston
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: BOS → SFO, nonstop flights by US airlines that report to the DOT. How we calculate this.