INDIANAPOLIS — A year ago, fans at the Indianapolis 500 were searching for shade.
This year, they'll be looking for some sun.
Temperatures throughout May have been unseasonably cool at Indianapolis Motor Speedway, and that hasn't changed during race weekend. Fans bundled up against the chill for the public drivers meeting Saturday – even the drivers appeared to be shivering – with more cool weather in store for Sunday.
The forecast for race day is a high in the upper 60s, according to the National Weather Service, with a 40 percent chance of rain. But it could be in the upper 50s when the green flag waves to start the "Greatest Spectacle in Racing," a huge departure from a year ago when most of the 235,000-plus fans were sweating things out.
The temperature hit 91 degrees when Dario Franchitti crossed the finish line, just one degree shy of the race-day record of 92 set in 1937. It was also 91 on race day in 1919 and 1953.
Many drivers believe the weather this year will produce more speed, but it's unclear whether it will benefit Honda engines or Chevrolets – or maybe just make everyone faster.
"I think cooler temperatures and lower humidity definitely helps the engines in general," said James Hinchcliffe, whose Andretti Autosport team has been fast all month with Chevrolet power.
Defending series champion Ryan Hunter-Reay said that the cars handled differently on Carb Day on Friday, when drivers had their final practice, than they did during warmer qualifying days.
Franchitti said that the colder temperatures might also produce a more competitive race.
"The way this car drafts, the big bulky bodywork, that also lends itself to close racing," the defending race-winner said. "The cold temperatures might help, as well."
The only time it hasn't cracked 60 degrees on race day happened in 1992, when Al Unser Jr. held off Scott Goodyear by 0.043 seconds for the closest finish in Indianapolis 500 history.
Rain has also played a role in several Indy 500s. Though the chance of precipitation is slim for the start of Sunday's race, it's expected to increase as the day wears on.
Pole sitter Ed Carpenter said the cooler temperatures are a relief to drivers in part because of the heavy fire suits that they wear. When the mercury rises, so does the temperature in the cars, and those fire suits become hot, bulky and often soaked-through with sweat.
"Mentally, it gets hard over 500 miles, especially if it's a hot day," he said. "It looks like it's going to be cool, but mentally this place will wear you down. There's not much margin for error at this race track. One mistake can end your day."