What is いつ doing in this sentence?

I’m going through Genki 1, and chapter 10 has the following sentence:
“What season do you like best?”
The only thing I don’t understand from it is what いつ is doing. Is it asking when is your favorite season?


Pretty much, yes.

Seasons are a time of year, after all. It’s like asking “when is your favourite time of day”.


Yes. If you look at the whole sentence, you’ll notice it doesn’t say 何の季節 (what season) so the only question indicator (sorry, don’t remember the proper grammar term at the moment) would be いつ.

It’s just in English, it’s natural to say “what season” vs. “when season” or a long winded way of “when is the season you like best?” Sounds odd right? Likewise, in the context of this sentence, いつ works most naturally.