Tracked live by the FAA, but its flight plan was first seen after takeoff, so we don't know the scheduled time and can't say whether it's late.

UNITED · FLIGHT UA 4209 LANDED 12:25 PM PT, ~37 MIN LATE · SCHEDULED TIME UNKNOWN

Wednesday, September 30

UA 4209 · BFI → SEA

took off 11:23 AM PT · landed 12:25 PM PT (scheduled time unknown)

Forecast issued Wed 10:00 PM ET · 8h after departure

Arrive at SEA more than 15 minutes late?

31% chance · ±0 pts +14 pts · 24h

HOW SURE WE ARE Very high. The odds now come almost entirely from live conditions.

What’s moving the odds

↑ Other factors

↑ UA's recent on-time record

↑ SEA is prone to delays

↓ Wednesdays in September are usually quieter than average

↓ 11am departures from BFI are usually not late

Weather at each end

BFI (origin) Gusts— Ceiling— Visibility— Precip—

SEA (destination) Gusts9 kt Ceiling1,300 ft Visibility10+ mi Precipnone

How this resolves

Yes if the gate arrival is more than 15 minutes after the scheduled arrival. Cancelled or diverted flights resolve N/A.

Every question here is display only — there is no betting or money involved. Gate times come from the airline; a cancellation resolves only the “Cancelled?” question, and a diversion voids the delay questions.

UA 4209 · BFI → SEA

Odds over time