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 4550 LANDED 7:03 PM MT, ~15 MIN LATE · SCHEDULED TIME UNKNOWN
Yesterday

WN 4550 · SLC → PHX

took off 6:33 PM MT · landed 7:03 PM MT (scheduled time unknown)
Forecast issued Tue 10:00 PM ET · 1h after departure

Odds over time

Arrive at PHX more than 15 minutes late?
41% chance · ±0 pts −5 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% 1.0d 12h 6h Departs Lands