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 4703 LANDED 8:23 AM ET, ON TIME · SCHEDULED TIME UNKNOWN
Today

WN 4703 · MIA → BWI

took off 6:14 AM ET · landed 8:23 AM ET (scheduled time unknown)
Forecast issued Sat 4:00 PM ET · 10h after departure

Odds over time

Arrive at BWI more than 15 minutes late?
15% chance · ±0 pts – · 24h
HOW SURE WE ARE Very high. The odds now come almost entirely from live conditions.
LIVE IN THE AIR 0% 5% 10% 15% 20% 3h Departs Lands