If your dashboard is anything like the recent vehicles I'm familiar
with, it's just a big plastic molding with a flexible, printed circuit
board on the back.  The lights are likely little "grain of wheat" bulbs
in twist-in holders.  I am guessing what has happened is that the
plastic has warped enough that when it's cold, the little "fingers" on
the twist in bulb bases aren't making proper contact with the flexible
printed circuit board.  I'd crawl under the dash, remove the bulbs, and
pry up the little metal contacts with my thumbnail so they make a
little tighter contact, then reinstall.  Hopefully that will be all you
need to do to make this work.  If you drive a lot at night you may just
want to replace all the bulbs now since you're going to be under there
and they're cheap.

good luck,

nate