Nobody did a better job racing until the raindrops fell than Tony Stewart.
Stewart got his second NASCAR victory of the season when rain shortened the race at Auto Club Speedway by 71 laps, extending the defending Sprint Cup champion's unusually strong start.
Kyle Busch finished second, and Dale Earnhardt Jr. added to his good start to the season in third.
"You hate to have it end with rain like that,'' Stewart said. "But we've lost some that way, and we didn't back into the lead.''
Stewart has won seven of the last 15 races, including Las Vegas last month, in a remarkable stretch of dominance for a driver who rarely gets rolling until summer.
Although Stewart sees nothing special about his approach to the new season, he's clearly focused. Stewart and new crew chief Steve Addington didn't mention the rain to each other until moments before it hit one end of the 2-mile oval, but they had already done the work necessary to win.
"It's been nice to get off to a good start this year the way we have,'' said Stewart, who has been even more impressive this year despite firing crew chief Darian Grubb last December. "The history shows the last 13 years, we haven't had the strongest start the first third of the year, but I'm really excited about the start we've got going. Daytona was probably our weakest race, and I know I made decisions trying to make things happen and it didn't work out. I'm really proud of what Steve and all our guys have done.''
Stewart's Chevrolet passed Busch 44 laps before the race was stopped when the looming rain clouds finally burst and halted a race run entirely on green flags to that point. Although a few drivers weren't happy when the race was called off after a delay of just over 30 minutes amid steadily worsening rain, Stewart collected his 46th career win and his second at Fontana.
"Playing to the weather, everybody is trying to get everything they can get toward the midway point of that race,'' Stewart said.
Defending race winner Kevin Harvick was fourth, and Carl Edwards was fifth. Greg Biffle, Edwards' Roush Fenway Racing teammate, finished sixth and kept a seven-point lead on Harvick atop the points standings.
"We had a great race car there from the start of the race,'' said Busch, who started second alongside teammate Denny Hamlin and took the lead on the second lap. "We led a lot of laps. I just wish we led 30 more.''
The drivers saw only blue skies at their meeting two hours before the race began, but the weather steadily worsened. The resulting drop in temperature threw off many teams' calculations on air pressure and other decisions, forcing adjustments on their first pit stops.
Realizing they might not be able to get much past the halfway point necessary to make a race official, the drivers mounted a fast, clean race on the extra-wide track, nearly setting the track record for consecutive green-flag laps until the rain finally forced a caution on the 125th lap.
"We all knew it was just going to be a matter of time,'' Busch said. "So probably at Lap 60 or 70, we were thinking, `OK, we're probably going to race to Lap 100.'''
The California track is known for its bumpy, wide asphalt that puts a premium on driver skill and strategy, but also is more susceptible to climate changes. Although most forecasts suggested the rain would stick around for a while, Hamlin went to Twitter to express his displeasure with NASCAR's decision to end the race with roughly five hours of daylight left.
"Never seen a race called at 2pm before,'' Hamlin tweeted. "1st time for everything. Strong weekend.''
After hitting the wall late in last week's race at Bristol, Stewart was back in top form. He earned his earliest win in a NASCAR season two weeks ago at Las Vegas with an aggressive move out of a restart, but the real racing at Fontana hadn't even started before rain hit.
"We didn't have an opportunity to do anything other than what we had planned from the start,'' said Earnhardt, who has finished in the top 15 in all five races this season. "I like how our season is going so far. If we keep going like this, maybe we can get some opportunities ... and seal the deal.''
The rain erased a potential disappointment for five-time Fontana champion Jimmie Johnson, who was 10th when the caution came out. He elected to pit, getting four tires and fuel - but moments later, his car started spitting smoke.
With no idea what was wrong with the car, crew chief Chad Knaus told Johnson to keep dripping oil on the course so he could keep his position if the race was red-flagged. The strategy worked, and the five-time Sprint Cup champions extended their streak to 10 straight top-10 finishes on this track.
"Either a piece of debris hit an oil line and knocked the fitting off, or split the line,'' Johnson said. "I was just idling along, and my friends pulled up alongside and said, `You're smoking.'''