> > > Can you get the ds1820 in a sealed package?
>
> I mean like shielded from the outside environment. So I can use it outdoor,
> -exposed to rain.

  Try coating it with a marine epoxy, I've done it and it worked fine.
  As long as you don't need fast response times to rapid temperature changes
  all should be well.  I'll be using it to measure water temperature and
  there will only be gradual temperature changes so I'm not worried about
  the additional thermal mass.

  Good Luck

  Jim Widman