For that matter zimowe is new as well (we had zima, but not the adjective derived from it).
I haven't seen it either. I got this one as a listening exercise and got it right by pure luck.
It doesn't accept if I put "the" in the beggining of the phrase... I wonder why.
I tried "cold days are shorts"... Well, often enough there is a correlation but still not the correct translation. Oups :D Maybe next time :)
The days in winter are short, not accepted is there a difference in translation?
"Dni w zimie", I guess. You changed an adjective into a noun.
Although... ok, added.