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 1783 LANDED 7:54 PM ET, ~14 MIN LATE · SCHEDULED TIME UNKNOWN

UA 1783 · LAX → BOS

took off 11:44 AM PT · landed 7:54 PM ET (scheduled time unknown)
Forecast issued Tue 10:00 PM ET · 7h after departure

Odds over time

Arrive at BOS more than 15 minutes late?
37% chance · ±0 pts +9 pts · 24h
HOW SURE WE ARE Very high. The odds now come almost entirely from live conditions.
WEATHER FORECASTS LIVE IN THE AIR 0% 15% 30% 45% 60% 2.8d 2d 1d 12h 6h Departs Lands