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 3652 LANDED 12:20 AM ET, ~7 MIN LATE · SCHEDULED TIME UNKNOWN
Yesterday

WN 3652 · DEN → BOS

took off 7:01 PM MT · landed 12:20 AM ET (scheduled time unknown)
Forecast issued Tue 10:00 PM ET · 1h after departure

Odds over time

Arrive at BOS more than 15 minutes late?
46% chance · ±2 pts −2 pts · 24h
HOW SURE WE ARE Very high. The odds now come almost entirely from live conditions.
WEATHER FORECASTS LIVE IN THE AIR 0% 20% 40% 60% 80% 1.0d 12h 6h Departs Lands