Photo credit: Brines.org
There is a huge variety of food available throughout the year in grocery stores in the US. In most places, this is due to several factors: far distant farms situated in temperate climate regions; varieties of plants that have been bred to produce food that will ripen slowly and be hardy enough to withstand the rigors of packaging and shipping; and a transportation infrastructure that brings them to our stores. Unless you live in a southern state, much of the produce in your local stores right now is being shipped from far away.
All that shipping has an associated cost (financial cost as well as energy use and carbon release). Locally grown food has many adherents. There are hundreds of farms operating as community supported agriculture (CSA), where people buy memberships in the farm and receive a share of produce (usually on a weekly basis). CSA farms are wonderful for getting food locally, but they are usually tied to the local growing season, meaning that they don't have produce during the winter. But other options can allow even more extension of the growing season.