Hot weeks in July are the worst time to have seeds sitting in a delivery van, since a few days above forty degrees in a metal box can cook the embryo without any visible change. Winter cold does far less damage. Padded and insulated mailers from https://budweedseeds.com are standard rather than an add on, and ordering early in the week avoids a parcel sitting in a depot over the weekend. If a summer batch germinates poorly, heat in transit is a likely reason before you blame genetics.
