I buy both tropical plants and orchids during the winter but mostly from vendors that hold the orchids until it is safe to ship. I know I can order from these vendors with confidence. Every once in a while, when warm weather is forecast, I might order from a vendor whom I know ships the orchids very quickly and will use a heat pack. It is very risky so I do this quite rarely. Before ordering from vendors during the winter, always make certain it is a vendor that knows what they are doing.
Many years ago, I ordered some orchids around Thanksgiving from two vendors (Hausermann's and Al's Orchid Greenhouse) as spouse suggested I buy some orchids for myself for Christmas. Just after ordering, winter arrived in full force. I ordered from another vendor (Oak Hill Gardens in Ill., now gone) in late January for Valentine's Day. All three vendors shipped the orchids the last week of March...it was a great week.