For how long where the light up in Phoenix' sky.?

Question

Phoenix Lights "The Lights over Phoenix"

Answer 1

The night of March 13, 1997.  There's a DVD about it called "The Phoenix Lights"

Answer 2

The Phoenix Lights is a name given to a series of optical phenomena and sightings that occured in the sky over Arizona, Nevada, and the Mexican state of Sonora on March 13, 1997.   Lights of varying descriptions were seen by thousands of people between 19:30 and 22:30 MST.

There were two separate events:

-a triangular formation of lights seen to pass over the state

- a series of stationary lights seen in the Phoenix area

Both events have been investigated and explained.

A similar incident occurred April 21, 2008, but this was later reported to be a prank (flares attached to hot-air balloons).