From my personal experience I’d have to say NO. Chihuahuas and other small dogs with short hair especially, do not like rain, cold, snow, cold, wind and cold. We love to be warm so if you must walk your Chi in inclement weather buy them a warm sweater or coat. We may balk at first, but it’s best to be warm than cold. I have a cute little pink parka that is fastened with velcro. It’s easy on and easy off. (No Affiliation.)
For all your pet shopping needs why not try PetSmart. It’s where I first went when I was adopted by my daddies. It’s also where I went to school and graduated with honors.