[s-cars] AUTO button on Climate Control

[JR]

Here's something that has been bugging me since I bought this car, but 
not enough to bring it to the front of my brain where I might ask why 
until now:  Why does the AUTO button on my climate control control panel 
ALWAYS turn the A/C compressor on?  I can set the temp to HI (well above 
80) on a subzero outside day and it will ALWAYS light up the snowflake 
and turn on the A/C compressor when I press it.  I would think that it 
would simply adjust the A/C, heater and fan so as to achieve the 
temperature that I select, but if I select a hot temperature or if it's 
cold outside, why the A/C compressor?  Is this normal or is my CC system 
wacky?

JR