I have mailed out in winter as well with no problems. If wanting to get them out of the way you should have no problem mailing now and he can store in fridge until ready.
If you are just dry storing them in the fridge they will be fine to ship. All of mine are in the fridge now and I have been shipping since June and will continue for the next few months.
Just put them in a padded bubble envelope and mail first class.
