Will i need a down jacket in milan, italy during 20-28december?

i'll flying europe on 20 december don't know wear! heard cities milan, rome , nice, visiting, aren't cold in winter, true? temperatures like?
have leather jacket pull , bear, it's thickest i've got , it's not stuffed down feathers or anything, 1 of kinds of fashionable jackets. enough?
have bring down jacket?

i'll flying europe on 20 december don't know wear! heard cities milan, rome , nice, visiting, aren't cold in winter, true? temperatures like? have leather jacket pull , bear, it's thickest i've got and...

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