"Rainy Dayz" is a song by American singer Mary J. Blige featuring additional vocals from rapper Ja Rule. Taken from Blige's re-release of her fifth studio album, No More Drama, the track was released to coincide with the release of the album's reissue, serving as its final single. The Irv Gotti-produced duet became another hit for both, peaking at number 12 on the Billboard Hot 100 and number 17 in the United Kingdom.

Mary Jane Blige is an American singer, songwriter, rapper, and actress. Often referred to as the "Queen of Hip-Hop Soul" and "Queen of R&B", Blige has won nine Grammy Awards, a Primetime Emmy Award, four American Music Awards, twelve NAACP Image Awards, and twelve Billboard Music Awards, including the Billboard Icon Award. She has been nominated for three Golden Globe Awards and two Academy Awards, including one for her supporting role in the film Mudbound (2017) and another for its original song "Mighty River", becoming the first person nominated for acting and songwriting in the same year.