INDIANAPOLIS -- Tens of thousands of fans are arriving at the Indianapolis Motor Speedway for what could be the hottest Indianapolis 500 on record.

Temperatures were forecast to climb into the mid-90s during Sunday's race, and many fans brought ice, extra water and misting fans with them for the "Greatest Spectacle in Racing." Laurie Smith of Fishers, Ind., and her 14-year-old son, C.J., even had a black umbrella for quick shade if needed.

Speedway officials spent the week urging fans to take precautions against the heat. The track has brought in portable misting stations and cooling stations, but spokesman Doug Boles predicts more than 1,000 fans will need medical treatment.

The National Weather Service in Indianapolis says the hottest race day on record was in 1937, when the temperature hit 92 degrees.