I ship every single month of the year, but I also pack my boxes based on temps. About 7 years ago I spent an entire winter experimenting with different boxes, heat pack combinations, and temperatures out on the back deck of my home overnight to find what specifically is needed in what temperature before I would ship a ball python in the winter months.

While I don't think it's advisable for someone who's never shipped in extreme temperatures before to just throw a snake and a heat pack in a box and drop it off, I do think that if you take the time to experiment and educate yourself that it can be done safely.

Hope this helps.

-adam