"Rainy Dayz" is a song by American singer Mary J. Blige featuring additional vocals from rapper Ja Rule.

Ja Rule wrote "Rainy Dayz" in response to the September 11 attacks in his home city of New York.

He told Complex, "I went in my basement in my studio and put that record together because that’s how I was feeling about the situation.

On the record, I’m basically saying that it’s these rainy days that we spend a lifetime trying to wash away.

"[3] Jason MacNeil, writing for PopMatters, noted that "Rainy Dayz" begins "with a horrid pace and structure, but thankfully moves into a much better vibe as some dense layering and keyboards gives it a decent tune.