The roots

Not FOR bigger container. I mean TO bigger container. Sorry, I can speak english, but my write is ummmh....mayby I learn....some day :)

I think your night time temperature is too cold, especially since the plant wouldn't get warmed up during the day. At 0C you could expect some damage starting on the plant. Your English is okay, better than some English-speaking people on the internet. And much better than my Finnish :-)

Our winter temperatures (in Phoenix) are very similar to your temps now, and these palms are very common planted outdoors. We regularly get below freezing temps at night, the only time I had frost damage on mine was when it dipped into the low 20's F, and even then it was fairly minimal. Mine was planted in a fairly protected spot, which I assume your balcony is a bit more protected than it would be out in a yard. I don't know how much difference being in a pot as opposed to growing in the ground would make, but they are a pretty tough palm.

Thank you. Kiitos! I think I am gonna keep it indoor until temperatures warming up.