Songfacts®:

• In this song, Stevie Wonder envisions the people of the world coming together in peace, a vision he shared with the reggae superstar Bob Marley. In this world, Zimbabwe is free from war ("Peace has come to Zimbabwe") and Third World countries are lifted from poverty ("Third World's right on the one").
  
  The song was not written as fantasy: Wonder really thought he could pull this off with Marley's help. The two met in 1975 when Wonder played a concert in Kingston to support the Jamaican Institute for the Blind (this would be the last time Marley performed with The Wailers). They became good friends and talked about holding a huge concert event where Marley would play his Survival album start to finish and Wonder would do the same with Journey Through the Secret Life of Plants (both albums were released in 1979).
  
  Plans for the project were thwarted when Marley got cancer; he injured his toe playing soccer in 1977, and when it became infected, he refused to have it amputated due to his Rastafarian beliefs, which led to the disease. The Hotter Than July album was released in September 1980; Marley died in May 1981.
  
  Wonder's grand vision may seem idealist, but he sometimes met his outlandish expectations: Another song on the album, "Happy Birthday," is a tribute to Martin Luther King, Jr., and Wonder's efforts to get King's birthday declared a national holiday paid off when US President Ronald Reagan signed it into law in 1983.
• Wonder pays tribute to Bob Marley in this song, using a reggae rhythm and mentioning Marley in the line, "Marley's hot on the box." The line, "Joined as children in Jah" is also a reference to Marley, as "Jah" is the Rastafarian name for God.
• The title is a reference to the Bob Marley song "Jamming," which appears on his 1977 album Exodus. Wonder's message is a take on what Marley espoused in that song, where "Jah children must unite" and they would be "jammin' in the name of the Lord." In Wonder's song, they are "Jammin' until the break of dawn."
• The phrase "Master Blaster" is never uttered by Wonder in this song: it is sung by the backup singers in the line, "We're in the middle of the makin's of the master blaster jammin'." In this context, the "Master Blaster" is God or whatever higher power you believe in.
• The album title comes from the opening line in this song: "Everyone's feeling pretty, it's hotter than July."