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 983 LANDED 3:44 PM ET, ~13 MIN LATE · SCHEDULED TIME UNKNOWN

UA 983 · ATH → IAD

took off 12:17 PM EEST · landed 3:44 PM ET (scheduled time unknown)
Forecast issued Tue 10:00 PM ET · 17h after departure

Odds over time

Arrive at IAD more than 15 minutes late?
6% chance · ±0 pts −1 pt · 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% 14h 12h 6h Departs Lands