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 997 LANDED 4:42 AM ET, ~10 MIN LATE · SCHEDULED TIME UNKNOWN
Yesterday

UA 997 · ACC → IAD

took off 10:36 PM GMT · landed 4:42 AM ET (scheduled time unknown)
Forecast issued Tue 10:00 PM ET · 3h after departure

Odds over time

Arrive at IAD more than 15 minutes late?
8% chance · ±0 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% 3% 6% 9% 12% 1.1d 1d 12h 6h Departs Now Lands