SFO to BOS flight delays & on-time performance
Nonstop flights from San Francisco International Airport to Boston Logan International Airport · 2,704 miles · Aug 2025 – Jul 2026
No FAA-reported ground stops or delays at SFO or BOS right now. Individual flights can still be delayed by the airline; check with your airline for your flight.
Key facts
- Flights from San Francisco (SFO) to Boston (BOS) arrived on time 76% of the time in Aug 2025 – Jul 2026, worse than the 78% national average.
- 1.7% were cancelled, and 10% arrived an hour or more late.
- United Airlines was the most punctual airline here (79% on time); Delta Air Lines was the least (73%).
- Departures scheduled around 6am did best (88% on time); around 10am did worst (65%).
- Saturday was the most reliable day to fly (83% on time) and Thursday the least (71%).
- The largest source of delay minutes was air traffic control & airport congestion (39%).
Which airline is most on time from SFO to BOS?
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 |
|---|---|---|---|---|---|
| United Airlines | 79% | 1.2% | 16 min | 8.6% | 1,904 |
| Alaska Airlines | 78% | 0.6% | 15 min | 9.3% | 173 |
| JetBlue | 73% | 2.4% | 22 min | 11.2% | 1,736 |
| Delta Air Lines | 73% | 1.5% | 20 min | 8.7% | 919 |
| Southwest Airlines | 0% | 0.0% | 49 min | 0.0% | 1 |
Best time of day to fly
On-time arrival rate by scheduled departure hour (local time).
- 6am88%181 flights
- 7am86%613 flights
- 8am81%558 flights
- 10am65%302 flights
- 11am66%328 flights
- 12pm68%453 flights
- 1pm71%386 flights
- 2pm76%91 flights
- 3pm73%412 flights
- 4pm86%183 flights
- 8pm83%154 flights
- 9pm74%437 flights
- 10pm77%178 flights
- 11pm77%422 flights
Best day of the week
On-time arrival rate by day of departure.
- Monday72%2.9% cancelled
- Tuesday75%1.7% cancelled
- Wednesday76%0.6% cancelled
- Thursday71%0.6% cancelled
- Friday77%0.8% cancelled
- Saturday83%0.9% cancelled
- Sunday78%4.0% 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 congestion39%
- Late-arriving aircraft36%
- Airline (crew, maintenance, cleaning, fueling)23%
- Extreme weather2%
- Security0%
Why flights are cancelled
Share of cancellations by reason.
- Extreme weather56%
- Airline (crew, maintenance, cleaning, fueling)24%
- Air traffic control & airport congestion20%
- Security0%
SFO to BOS: common questions
- How often are SFO to BOS flights on time?
- 76% 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 San Francisco to Boston cancelled?
- 1.7% of scheduled flights were cancelled (79 of 4,733).
- How long are typical delays?
- Across all flights the average arrival delay was 19 min (early arrivals count as zero). Flights that were late arrived 75 min behind schedule on average, and 9.6% of flights were an hour or more late.
- How long is taxi time at SFO?
- Flights on this route spent 23 min taxiing from the gate to takeoff on average.
Related routes
Return trip: BOS to SFO — 72% on time
More flights from San Francisco
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. Route: SFO → BOS, nonstop flights by US airlines that report to the DOT. How we calculate this.