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 4572 LANDED 11:39 PM ET, ~2 MIN LATE · SCHEDULED TIME UNKNOWN

WN 4572 · MDW → GRR

took off 10:14 PM CT · landed 11:39 PM ET (scheduled time unknown)
Forecast issued Fri 10:00 PM ET · 1h before departure

Odds over time

Arrive at GRR more than 15 minutes late?
37% chance · ±1 pts – · 24h
HOW SURE WE ARE High. The odds now come mostly from live FAA and airport data.
LIVE IN THE AIR 0% 15% 30% 45% 60% 2h Now Departs