DAYTONA BEACH, Fla. - One of the most valuable pieces of equipment on pit road during tonight's Coke Zero 400 will be weather radars.

Rain and thunderstorms are part of the every day routine at Daytona International Speedway during the summer months. This year hasn't been any different with showers delaying Thursday's practice and washing out Friday's qualifying.

With rain a possibility for tonight's main event (8 p.m., TNT), drivers and crew chiefs will have a lot to think about. The 2.5-mile tri-oval is worn, slick and bumpy. Tires are wearing out quickly and restrictor-plate racing brings the very real threat of a multi-car accident. And rain has the potential to cut the ending short anytime between laps 81-160.

"We all have radar systems to know what is going on, but at the same time, when you get to the halfway mark and everybody is racing around crazy when you know that rain is in the area and the word has been put out," Jimmie Johnson said.

Three races have been stopped short of their scheduled finishes this year, and two of them were won by teams that gambled to stay on the track without adding gas because they knew of the weather situation.

"We normally watch the radar pretty closely, and while you can't predict everything that pops up on the radar these days, especially here in Florida, I think you have to be prepared for anything and you have to race pretty hard throughout the race," Jeff Gordon said. "Once you get to the halfway point or as you're closing in on the halfway point, if it looks like the potential for rain then you're going to see guys racing a lot harder. We saw it last week, and we've seen it in the past. I think we'll see it again here."

Jeff Burton is one of the few drivers in the field who used to drive when the race started at 10 a.m. 12 years ago. The speedway used to tell fans they could be on the beach by 1 p.m. The Brumos 250 for the Grand American Sports Car Series at 2 p.m. today means fans will be at the track all day.

"I like the morning because I can remember leaving here race day and being home, back in Charlotte, in time to be on the lake," Burton said. "It was kind of fun and coming down here was always kind of like a vacation. The teams, we would practice in the morning, the garage would be closed down by 1 o'clock or 12 o'clock, the way I remember it. Back then the teams weren't so big that they're families would come down and they would rent hotels on the beach and it was just a completely different environment, it was much more relaxed than it is now.

"This was almost like a race and an off-weekend at the same time. We don't really have that atmosphere anymore. The intensity has picked up so much and it's so competitive that there's never a relaxed moment. It was fun to race at 10 o'clock, at the same time I think the fans like the night race a lot better. Obviously, it gets cooler as the race goes on versus it used to get hotter as the race would go on. But you would be done really so it wasn't that bad. It is hot here, but it's just what we do."

With Friday's rainout, series leader Tony Stewart will start on the pole. Gordon will be second, followed by Johnson, Kurt Busch, Carl Edwards, Denny Hamlin and Ryan Newman.

The lineup was set by the car owner standings.