Which phrase would you use to describe a chilly atmosphere?

Describing a chilly atmosphere is best done with the phrase "It's cold," as it directly conveys the low temperature associated with a chilly environment. The term 'cold' specifically indicates that the air feels cool and uncomfortable, which aligns perfectly with what one would experience in a chilly setting.

In contrast, the other phrases do not accurately capture the essence of a chilly atmosphere. For instance, "It's raining" suggests wet weather without implying temperature, while "It's hot" clearly denotes warmth, which contradicts the idea of a chilly atmosphere. Lastly, "It's cloudy" describes the state of the sky but does not provide any information about temperature, leaving the feeling of chill unaddressed. Thus, "It's cold" is the most suitable phrase to describe a chilly atmosphere.