United Airlines SFO to BOS on-time performance
United Airlines nonstop flights from San Francisco to Boston · Aug 2025 – Jul 2026
On-time arrivals
79%
arrived < 15 min late
Cancelled
1.2%
22 flights
Avg arrival delay
16 min
73 min when late
Rank on route
#1 of 5
route average 76% on time
Key facts
- United Airlines flights on SFO to BOS arrived on time 79% of the time in Aug 2025 – Jul 2026.
- 1.2% were cancelled, and 9% arrived an hour or more late.
- That ranks #1 of 5 airlines on this route, which averaged 76% on time overall.
- The largest source of delay minutes was air traffic control & airport congestion (46%).
On-time trend by month
Why this airline's flights were late
- Air traffic control & airport congestion46%
- Late-arriving aircraft33%
- Airline (crew, maintenance, cleaning, fueling)19%
- Extreme weather2%
- Security0%
Other airlines on SFO to BOS
- JetBlue73% on time · 22 min avg delay
- Delta Air Lines73% on time · 20 min avg delay
- Alaska Airlines78% on time · 15 min avg delay
- Southwest Airlines0% on time · 49 min avg delay
Full SFO to BOS comparison →
United Airlines on-time record across all routes →
1,904 United Airlines flights tracked on this route; 22 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.