Do all the cluster lights go out? Or only certain ones or a certain side? I've seen this problem lots where the filament in the bulbs gets a very minor break in it and when it gets cold it pulls the filament apart just enough to not make a full connection. But as it warms up it'll pop back on by itself. I had that happen recently to my crx when it started getting colder here and just went ahead and replaced all the bulbs in my cluster.