I think there are 2-3 possible explanations.  The first 2 mean a new clock.

If it's the LCD display crapping out (assuming it's a digital clock), then
the clock should still be reading the right time when the display re-
appears.  Liquid crystal displays can be temperamental, but I doubt the
temperature is getting low enough.  It's more likely the internal clock
oscillator is stopping.  I doubt there's a practical fix either way.

BUT it wouldn't hurt to poke around for flaky electrical connections.  These
can be temperature sensitive, too.  You might be lucky.

//Jack

> I own a 1984 passenger Vanagon and it seems like when the colder weather hits
> here in Florida down below 70's at night I have my clock in the dashboard
> stop  and when it warms up the next day it resumes....whats the most likely
> problem?
>