In English, we usually use it is or it's when we talk about the weather.
It is + weather word is a description of the weather
We can also say:
It is a + weather word + day (or morning/afternoon/night)
It is + weather word+ing = This type of weather is happening now.
Questions about the weather - Asking about the weather 询问有关天气的问题
People ask about the weather by saying: 有关天气的问题