Why is it "zimy"? I would expect it to remain in Nominative "zima" since no verb is used in this sentence. Please explain why it becomes "zimy" and what case it is. Many thanks.
The difference between Polish "y" and "i", at least from what I've been hearing from the audios, don't take my word too seriously, is that "y" is a short "i" (and actually, it works for me when I shape my mouth more like an "i" in "in" but instead try to pronounce a soft "e" such as in "meh").