United Airlines ONT to SFO on-time performance
United Airlines nonstop flights from Ontario to San Francisco · Aug 2025 – Jul 2026
On-time arrivals
69%
arrived < 15 min late
Cancelled
0.4%
4 flights
Avg arrival delay
21 min
65 min when late
Rank on route
#1 of 3
route average 62% on time
Key facts
- United Airlines flights on ONT to SFO arrived on time 69% of the time in Aug 2025 – Jul 2026.
- 0.4% were cancelled, and 10% arrived an hour or more late.
- That ranks #1 of 3 airlines on this route, which averaged 62% on time overall.
- The largest source of delay minutes was air traffic control & airport congestion (58%).
On-time trend by month
Why this airline's flights were late
- Air traffic control & airport congestion58%
- Late-arriving aircraft21%
- Airline (crew, maintenance, cleaning, fueling)19%
- Extreme weather2%
- Security0%
Other airlines on ONT to SFO
- Frontier Airlines39% on time · 43 min avg delay
- SkyWest Airlines42% on time · 37 min avg delay
Full ONT to SFO comparison →
United Airlines on-time record across all routes →
981 United Airlines flights tracked on this route; 4 cancelled, 0 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.