T.M.
Our is 18x48. My husband drains it, dries it really good and stores it in the garage. The first one we had when my daughter was in kindergarten. She is in 9th grade now. The only reason why we replaced it was we were nervous. I was afraid the seems were getting old. Intexs are amazing :)
I really think you should store it. I don't think they were made to withstand the winter. It may tell you on the website.