UA643 SEA → SFO

United Airlines · Seattle, WA to San Francisco, CA · 19 flights observed, 2025-12-18 to 2026-01-05 · 679 mi

This flight has been on time less than half the time (42%) — expect a real chance of a delay.

UA643 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
42%
Median delay
+21 min
90th percentile
+48 min
Cancellation rate
0%

How often is UA643 on time?

Across 19 flights on SEA → SFO from 2025-12-18 to 2026-01-05, UA643 arrived within 15 minutes of schedule 42% of the time. The median arrival delay was +21 min, and the worst 10% of flights arrived +48 min or later. 0% of flights were cancelled.

Delay distribution

Arrival delay for completed flights (excludes cancellations and diversions).

ArrivalFlightsShare
Early / on-time842%
16-30 min526%
31-60 min526%
61-120 min15%
2+ hrs00%

Performance by month

MonthFlightsOn-timeAvg delay
2025-121443%+16 min
2026-01540%+22 min

Performance by day of week

DayFlightsOn-time
Mon333%
Tue250%
Wed250%
Thu30%
Fri333%
Sat367%
Sun367%

Based on US Department of Transportation Bureau of Transportation Statistics on-time data. Loading live conditions and full charts…