United Airlines BOS to SFO on-time performance
United Airlines nonstop flights from Boston to San Francisco · Aug 2025 – Jul 2026
On-time arrivals
75%
arrived < 15 min late
Cancelled
1.3%
24 flights
Avg arrival delay
18 min
67 min when late
Rank on route
#2 of 5
route average 72% on time
Key facts
- United Airlines flights on BOS to SFO arrived on time 75% of the time in Aug 2025 – Jul 2026.
- 1.3% were cancelled, and 9% arrived an hour or more late.
- That ranks #2 of 5 airlines on this route, which averaged 72% on time overall.
- The largest source of delay minutes was air traffic control & airport congestion (47%).
On-time trend by month
Why this airline's flights were late
- Air traffic control & airport congestion47%
- Late-arriving aircraft28%
- Airline (crew, maintenance, cleaning, fueling)21%
- Extreme weather4%
- Security0%
Other airlines on BOS to SFO
- JetBlue69% on time · 22 min avg delay
- Delta Air Lines71% on time · 20 min avg delay
- Alaska Airlines60% on time · 29 min avg delay
- Southwest Airlines100% on time · 7 min avg delay
Full BOS to SFO comparison →
United Airlines on-time record across all routes →
1,905 United Airlines flights tracked on this route; 24 cancelled, 4 diverted.
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. How we calculate this.