Flight OddsUA2121 SEA → SFO
United Airlines · Seattle, WA to San Francisco, CA · 53 flights observed, 2026-03-29 to 2026-05-20 · 679 mi
UA2121 covers more than one route in the data window — the stats below are for SEA → SFO, the one it has flown most recently. The others are linked under “Other routes”.
On-time arrival
13%
Median delay
+44 min
90th percentile
+106 min
Cancellation rate
2%
How often is UA2121 on time?
Across 53 flights on SEA → SFO from 2026-03-29 to 2026-05-20, UA2121 arrived within 15 minutes of schedule 13% of the time. The median arrival delay was +44 min, and the worst 10% of flights arrived +106 min or later. 2% of flights were cancelled.
Delay distribution
Arrival delay for completed flights (excludes cancellations and diversions).
| Arrival | Flights | Share |
|---|---|---|
| Early / on-time | 7 | 13% |
| 16-30 min | 9 | 17% |
| 31-60 min | 16 | 31% |
| 61-120 min | 15 | 29% |
| 2+ hrs | 5 | 10% |
Performance by month
| Month | Flights | On-time | Avg delay |
|---|---|---|---|
| 2026-03 | 3 | 0% | +156 min |
| 2026-04 | 30 | 13% | +45 min |
| 2026-05 | 19 | 16% | +77 min |
Performance by day of week
| Day | Flights | On-time |
|---|---|---|
| Mon | 8 | 0% |
| Tue | 8 | 13% |
| Wed | 8 | 13% |
| Thu | 7 | 14% |
| Fri | 6 | 0% |
| Sat | 7 | 29% |
| Sun | 8 | 25% |
Other routes
Related
Based on US Department of Transportation Bureau of Transportation Statistics on-time data. Loading live conditions and full charts…