No it's not!
AC systems have always had low temp cutouts on them, and it's not idiocy for
the above poster. The ac is called for anytime the defrost is selected on
most cars but is prevented from cutting in below 40 F because below that
temp the gaseous refrigerant will liquefy and as we all know you can not
compress a liquid. It cuts it out so that your compressor doesn't smash to
little bits trying to compress liquid refrigerant.
Short lesson in refrigeration, compressor draws in low pressure gas, pumps
out high pressure gas. High pressure gas condenses into a liquid under
pressure in... what else but the condenser (that other rad in the front of
your car). High pressure liquid is metered/sprayed into the evaporator
where it becomes a low pressure gas again and so on.

For the OP, cars with persistant high humidity situations sometimes have
water leaks that may not be apparent. I had a Supra that leaked water at
the hatch. Windows seemed to fog easily. Discovered one day that the spare
tire well was half full of water.
Steve
<MajorDomo@mailcity.com> wrote in message
news:41C78298.78A50057@mailcity.com...
> The deactivation on newer domestic and automotive AC's, at 40
> degrees, is a federal regulation intended to save energy. Same
> as the limit on water capacity for toilets and the latest washing
> machines sold in the US. Your government at work.
>
>
> mike hunt
>
>
>
> "Gary L. Burnore" wrote:
> >
> > On Mon, 20 Dec 2004 15:43:59 -0500, Abeness <news@nada.x> wrote:
> >
> > >C. E. White wrote:
> > >> Unfortunately most A/C systems don't run once the
> > >> temperature drops below 40 degrees Fahrenheit.
> > >
> > >I don't believe this holds true for automotive systems. On my old
> > >Pontiac the A/C was directly tied to the defroster setting--switch the
> > >system to defrost, and the A/C was activated.
> >
> > It depends on the make/model. My cressida shuts the A/C off if you
> > turn the inside temp past 75%.
> >
> > >Good way to keep the compressor oils circulating to keep the seals
lubricated, in addition to
> > >removing condensation. Worked at any temp, as I recall, and I move
> > >around NY/New England.
> >
> > It does help with condensation. There's no doubt about that.
> >
> > >I'll confirm this on my new 94 Civic in a few days, as it has now
gotten
> > >cold enough around here to check. Disabling it below 40 degrees would
be
> > >idiocy--it's the only way to remove condensation effectively.
> >
> > I'm pretty sure that even in his case, it's the temp you set the
> > control to and not the outside temp.
> >
> > >It is true, however, that many room A/Cs don't function when the
outside temp
> > >is "too low"--which occasionally annoys me.
> >
> > There's a way to fix that, put a plastic bag over the outside of the
> > A/C after poking several holes in it. (The bag, duh).