The Indianapolis 500 is traditionally held in May.
The race is part of a month-long celebration at Indianapolis Motor Speedway, with practice, qualifying, and other events taking place throughout May before the race itself. The main event is usually scheduled for the Sunday of Memorial Day weekend, near the end of the month.
This timing is connected to the event’s long history. The first Indianapolis 500 was run on May 30, 1911, and the race’s identity became closely tied to springtime in Indiana. Fans often refer to the entire buildup as the “Month of May,” not merely to race day.
May is the traditional month, not an absolute rule for every year. The 2020 Indianapolis 500 was postponed to August because of the COVID-19 pandemic, making it an unusual exception. That change is why “traditionally” matters in the question.