For 1 degree in a range of -30 to +30, you only need to resolve 1 part in 60, or 6 bits. Is anyone seriously suggesting that Vcc from a regulator is going to mess this up ? Most reg are stable to 1 part in 100 over the full load range, and a linear reg should put out noise at much less than 1 part in 60 or you are going to get trouble with just about any other analogue circuitry.

As a very dirty solution to a very dirty measurement, using Vcc isn't that far out of spec, especially if you use a potentiall divider and a final cap as a filter.

Before I get flamed..PLEASE NOTE I WOULD NEVER DO IT MYSELF.....

;-))

Steve