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.

SOUTHWEST · FLIGHT WN 4431 LANDED 10:51 PM ET, ~14 MIN LATE · SCHEDULED TIME UNKNOWN

Tuesday, September 29 Yesterday

WN 4431 · BWI → BOS

took off 9:38 PM ET · landed 10:51 PM ET (scheduled time unknown)

Forecast issued Tue 10:00 PM ET · 0h before departure

Arrive at BOS more than 15 minutes late?

71% chance · ±2 pts +15 pts · 24h

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

What’s moving the odds

↑ Cloud base down to 600 ft, visibility down to 1.5 mi forecast at BOS that day

↑ Arrivals into BOS at that hour are often late

↑ 9pm departures from BWI are often late

↓ Tuesdays in September are usually quieter than average

↓ Mostly benign weather forecast at BWI

Weather at each end

BWI (origin) Gusts7 kt Ceiling3,600 ft Visibility9.2 mi Precipnone

BOS (destination) Gusts11 kt Ceiling600 ft Visibility1.5 mi Precip0.03 in

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.

WN 4431 · BWI → BOS

Odds over time