ON TIMEBOARD

UA 684 on time

United Airlines 684: Washington to Los Angeles at 3:15 p.m.; Los Angeles to Seattle at 6:58 p.m. (past 12 months). Figures below the title are for IAD → LAX, its busiest leg

On time
87%
134 flights · likely 80–91%
Cancelled
0.0%
of scheduled flights
Typical arrival
−9 min
median vs schedule
When late
+58 min
average delay
Similar flights
86%
UA, same route & hour

About 1 in 7 UA 684 flights from Washington arrived 15+ minutes late, diverted or cancelled over the past year (13%); 0.0% were cancelled. The typical flight landed 9 minutes early.

UA 684: IAD → LAX

Scheduled to leave Washington at 3:15 p.m. local time. Over the past year it arrived on time 87% of the time (134 flights), in line with other UA flights on the route at that hour (86%). Last seen in the data Aug 10, 2026.

Month by month

40%70%100%Mar 2026: too few flights (3 flights)MarApr 2026: 97% on time (30 flights)97AprMay 2026: 94% on time (31 flights)94MayJun 2026: 83% on time (30 flights)83JunJul 2026: 80% on time (30 flights)80JulAug 2026: too few flights (10 flights)Aug

By day of week

DayFlightsOn time
Monday2090%
Tuesday19—
Wednesday19—
Thursday19—
Friday19—
Saturday18—
Sunday2090%

Why it was late

Late inbound plane 34%Severe weather 28%Air traffic & airport (NAS) 22%Airline (crew, maintenance, ops) 16%

All flights IAD → LAX · Connecting off UA 684? Check the risk

UA 684: LAX → SEA

Scheduled to leave Los Angeles at 6:58 p.m. local time. Over the past year it arrived on time 84% of the time (122 flights), in line with other UA flights on the route at that hour (87%). Last seen in the data Aug 31, 2026.

Usually United Airlines's last flight of the day from Los Angeles to Seattle (100% of days). United Airlines's last LAX–SEA flight was cancelled 0.0% of the time, against 0.8% for its earlier ones. If it's cancelled, the next United Airlines flight is usually around 11:43 a.m. the next morning.

Month by month

40%70%100%Dec 2024: too few flights (2 flights)DecMar 2025: 85% on time (26 flights)85MarMay 2025: 77% on time (31 flights)77MayJun 2025: 70% on time (30 flights)70JunJul 2025: 77% on time (30 flights)77JulAug 2025: 71% on time (31 flights)71AugSep 2025: 93% on time (30 flights)93SepOct 2025: 88% on time (25 flights)88OctMay 2026: too few flights (9 flights)MayJun 2026: 70% on time (20 flights)70JunJul 2026: 82% on time (17 flights)82JulAug 2026: 76% on time (21 flights)76Aug

By day of week

DayFlightsOn time
Monday2391%
Tuesday8—
Wednesday11—
Thursday2378%
Friday2282%
Saturday13—
Sunday2277%

Why it was late

Late inbound plane 50%Airline (crew, maintenance, ops) 31%Air traffic & airport (NAS) 19%

All flights LAX → SEA · Connecting off UA 684? Check the risk

Questions

How often is UA 684 from IAD to LAX late?

United Airlines 684 from Washington, DC to Los Angeles, CA arrived 15 or more minutes late, was diverted or was cancelled on 13% of 134 scheduled flights between September 2025 and August 2026. 0.0% were cancelled.

How often is UA 684 from LAX to SEA late?

United Airlines 684 from Los Angeles, CA to Seattle, WA arrived 15 or more minutes late, was diverted or was cancelled on 16% of 122 scheduled flights between September 2025 and August 2026. 0.0% were cancelled.

Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check United Airlines for today's flight. Method.