"される” is the passive.
That window is broken (by my brother).
If you want to emphasis objects,you can use "される”
In passive sentence, the importance is objects or things.
In the winter,when you want to stay with someone to be warm or you feel very loneliness because of the weather is very cold, you can use 人肌が恋しい季節.
the meaning is that the season when you are missing warm from person.
It is a kind of usual phrases in letter or when you meet person who met very long time ago.
for example 人肌の恋しい季節になりましたが、お元気にお過ごしでしょうか。
In English, the season is winter and I am missing warm, how are you?
Usually, if we see this phrase we guess the season is getting cold.