Now i've had breeders ship me snakes when the temps were in the teens. Now he only did this because he is Will Bird and has shipped tons of snakes in his life with few DOA's. Other breeders who don't care as much about shipping wont take every precaution, so you do have to worry about shipping when temps are below 35 degrees.

I would try and buy local or buy from a REPUTABLE and WELL KNOWN breeder. Nothing against small breeders, but if you have a DOA, it's not always easy to get a replacement or refund from a small breeder.

I have had multiple snakes shipped to me with no issues, just know the seller and trust them.