[mesmark]

"There is rain today." sounds wrong to me. I'd say "It's going to rain today."

A: This afternoon's game was canceled.
B: It's raining. (not *There is rain today.)

A: I have to get out and mow the lawn now.
B: Why?
A: It's going to rain today. (not *There is rain today.)

bread_baker - can you give me a context where you'd use *There is rain today.