DOG FAQ - Is it safe to take Chihuahua on a cold weather walk?

Owners must be very sensitive to the fact that short-haired Chihuahuas, and even long-haired ones, are vulnerable to the cold. In temperatures of 35-40 degrees Farenheit, I would recommend dressing your Chihuahua in a special dog sweater for brief walks. Walking your Chihuahua in temperatures below 35 degrees Farenheit is strongly discouraged, especially when there is a wind-chill factor. In this, as in other aspects of dog maintenance, keep your dogs' health top priority, not your own desire. In some cold regions, an indoor heater will be necessary to keep your Chihuahua comfortable.

Chihuahua - Dog Lover