Fans carry umbrellas into Spa for thrilling race (GMM) Spectators filed into the Spa-Francorchamps circuit on Sunday morning carrying rain jackets and folded umbrellas.
There have already been a couple of early morning showers in the Belgian Ardennes, and although the asphalt is currently drying under overcast skies, the likely weather for the race at 2pm is anyone's guess.
The safest prediction at present is for an unpredictable wet and dry 44 laps.
"I'd like it to be dry to start with to make up some places, then a few showers as I don't mind driving in the wet at all," said Jenson Button, to start from fifth on the grid.
"If that is the case then anything could happen," he added.
Before driving into post-qualifying parc ferme on Saturday, the 2010 field opted for a mix of dry and wet setups.
"You have to be flexible," said Williams' Nico Hulkenberg. "I think the weather will change at least ten times in the race."
Fernando Alonso, who qualified a disappointing tenth despite earlier seeming to be at the wheel of a competitive Ferrari, said on Saturday: "What we know is that the chance of rain for tomorrow is stronger than it was today.
"I think that of the five drivers fighting for the championship, there will be some who do not finish this race due to the conditions," he added.
One crucial variable is that this weekend's conditions have been so changeable that most drivers are running low on intermediate tires.
"If the weather in the race keeps changing, then no one will have enough tires," admitted Red Bull's Christian Horner.
Alonso agrees: "If it's like it was today (Saturday), I think at some point or another we will all be on tires that are not the best for the conditions.
"It will be a problem but also an opportunity not to win half a second, but maybe ten seconds per lap. Tomorrow is a race to control and seize all the opportunities that may arise," added the Spaniard.