Ozzy Osbourne - classic heavy metal anniversary

September 20, 1980 (UK): Ozzy Osbourne - Blizzard of Ozz - Jet Records

March 27, 1981 (USA): Ozzy Osbourne - Blizzard of Ozz - Jet Records

The Metal Archives shows: "The album was released on September 20th, 1980 in the UK, and on March 27th, 1981 in the USA."

On the other hand, according to Wikipedia the UK date us September 12, "Blizzard of Ozz is the debut studio album by the English heavy metal singer Ozzy Osbourne. Released on 12 September 1980 in the UK and on 27 March 1981 in the US, the album was Osbourne's first release following his firing from Black Sabbath in 1979. Blizzard of Ozz is the first of two studio albums Osbourne recorded with guitarist Randy Rhoads prior to Rhoads' death in 1982."

Ozzy Osbourne - Revelation (Mother Earth)