Yes, you are right, however this sentence means probably something different ("That summer was a good period of my life"). By the way, "Seasons" translates to "pory roku".

This is one of several cases where you knowing the literal translation is more important than "making it sound right". The further you get from a language's family tree, the more often you can't always count on there being a literal translation of a word. English has such an astounding wealth of Romance loanwords that it's easy to forget how little intelligibility there actually is between branches of a major language family. (I'm noticing Polish has a decent amount of Romance loanwords as well, just for completely different things!)

You can check here: https://www.duolingo.com/comment/16373167

"time" is accepted, but here, Summer IS a good time :)