Among those killed is a man who was shot near a holiday party in the South Shore neighborhood late Monday.
Police say neighbors reported hearing a loud argument just before shots were fired and partygoers ran from the scene. The Cook County medical examiner's office says 33-year-old Malcolm Dowdy was pronounced dead at Jackson Park Hospital and Medical Center.
Last year, four people were killed in Chicago during the Memorial Day weekend, but bad storms that year forced many people to stay at home. This year the city experienced record temperatures that peaked in the mid-90s.