Final answer:
The subject of this question is English, and the grade level is High School. The sentence provided is an example of using language to describe the weather.
Step-by-step explanation:
The subject of this question is English because it relates to the understanding and interpretation of the meaning of the sentence.
The grade of this question is High School because it requires an understanding of language and grammar concepts.
The sentence 'It's a very warm day for February / Today is a really warm day for February' is an example of using language to describe the weather.