Flight OddsUA4639 ONT → SFO
United Airlines · Ontario, CA to San Francisco, CA · 19 flights observed, 2025-12-18 to 2026-01-05 · 363 mi
UA4639 covers more than one route in the data window — the stats below are for ONT → SFO, the one it has flown most recently. The others are linked under “Other routes”.
On-time arrival
47%
Median delay
+19 min
90th percentile
+74 min
Cancellation rate
0%
How often is UA4639 on time?
Across 19 flights on ONT → SFO from 2025-12-18 to 2026-01-05, UA4639 arrived within 15 minutes of schedule 47% of the time. The median arrival delay was +19 min, and the worst 10% of flights arrived +74 min or later. 0% of flights were cancelled.
Delay distribution
Arrival delay for completed flights (excludes cancellations and diversions).
| Arrival | Flights | Share |
|---|---|---|
| Early / on-time | 9 | 47% |
| 16-30 min | 2 | 11% |
| 31-60 min | 4 | 21% |
| 61-120 min | 3 | 16% |
| 2+ hrs | 1 | 5% |
Performance by month
| Month | Flights | On-time | Avg delay |
|---|---|---|---|
| 2025-12 | 14 | 57% | +17 min |
| 2026-01 | 5 | 20% | +83 min |
Performance by day of week
| Day | Flights | On-time |
|---|---|---|
| Mon | 3 | 0% |
| Tue | 2 | 50% |
| Wed | 2 | 100% |
| Thu | 3 | 67% |
| Fri | 3 | 33% |
| Sat | 3 | 67% |
| Sun | 3 | 33% |
Other routes
Related
Based on US Department of Transportation Bureau of Transportation Statistics on-time data. Loading live conditions and full charts…