Season is estação do ano (summer, spring, autumn, winter). Temporada is a short period of something, even a game, similar to época (epoch). A temporada de gripe ocorre nos próximos 3 meses (flu season is for the next 3 months)
Most words ending in -ção are feminine -- a function of the forms of the language: feminine words mostly refer to most females, rather than sex referring to feminine gender. (P.D. : ç is NOT the same as c; use the cedilla for the ss sound before a o u.)
Estação is a feminine word. Every noun in Portuguese has gender amd it is good to learn them along with the article in order to get it! =) As for the gender, it is not related to the "sex" of the word itself.