Antarctica cruise w/ Silversea - temperatures on board?

[MillyDM]

Hello there,

we're soon leaving for our first cruise to Antartica on Silversea. 
As we're traveling light with just a carry-on, we want to ensure we bring the right gear with us.

So we're wondering if the temperature on the ship will be cooler or warmer... Maybe this is a silly question, but we're
not sure what to expect.
Do we need warm layers to wear for our days on board (think of winter attire), or, if the temperature is on the warmer side, need just

spring/ medium layers?

It'd be great to know from those who've been on an Antarctica cruise with Silversea!

thank you!
milly