눈 snow.

날씨가 나쁘죠?

너무 추워요.  눈이 와요. 온 세상이 얼어붙었어요! (얼어붙어요 = is freezing. 얼어붙었어요 = has frozen; is in frozen state)

내일 날씨는 어떨까요 [or 내일은 날씨가 어떨까요]?

추울 거예요 [or 춥겠죠]!  (추울 거예요 = 추울 것이에요 = future tense.  춥겠죠 = It would be cold - adds more conjecture)

* 날씨는 - Since you already talked about today's weather, 은/는 is more appropriate when mentioning tomorrow's weather.  은/는 has the nuance of contrasting things, like "as for tomorrow", so it works well in this context.