To describe what is actually happening right now, you use the verb form: It is raining. To describe the sort of day it is, you use the adjective form: Today is a rainy day. In your first sentence, either rainy or raining could fit, depending on what you actually want to say; "...

Understanding the Context

because it is raining" indicates that water is physically falling from the sky right now, while "because it is ... 2 “Monday is rainy” — context, registers, and writing systems: “Monday is rainy” is not normal unmarked English. Native speakers would typically say: Monday was rainy (past observation) Monday will be rainy (future prediction). The original poster, however, drew this from a spreadsheet for early childhood teaching.

Key Insights

word usage - Is it wrong to say "Monday is rainy"? - English Language ... What are the best foods to have on a rainy day? What are the best foods to have for a rainy day? Which preposition would be appropriate here?

Final Thoughts

grammar - ON a rainy day or FOR a rainy day? - English Language ... Is it correct to say " Today is rainy" (or " Tomorrow will be frost.")? Normally I mention the time-expression in the end of the sentences as I was taught in past. For example: It is rainy today. It will be frost tomorrow.

But in the first examples that I'm asking about them, there's neither subject pronoun nor time-expression in the end. That's why I'm asking my question. word order - "Today is rainy" Vs. "It's rainy today." - English ...