It needs many hours of sun and high temperatures to grow, that's why it is mainly found in summer. The eggplants you buy in the middle of winter will most likely come from heated greenhouses or from distant countries.
Growing time
Top 3 of the producing provinces
Source: Ministry of Agriculture (2015). Statistical Yearbook.
How much is imported, how much is exported?
Source: Ministry of Economy (2015). Includes production in greenhouses.