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 1420 LANDED 11:04 PM MT, ~2 MIN LATE · SCHEDULED TIME UNKNOWN
Yesterday

WN 1420 · PHX → BOI

took off 8:27 PM MT · landed 11:04 PM MT (scheduled time unknown)
Forecast issued Tue 10:00 PM ET · 2h before departure

Odds over time

Arrive at BOI more than 15 minutes late?
44% chance · ±0 pts +3 pts · 24h
HOW SURE WE ARE High. The odds now come mostly from live FAA and airport data.
WEATHER FORECASTS LIVE IN THE AIR 0% 15% 30% 45% 60% 1.0d 12h 6h Now Departs Lands