Rain and shine at typical Spa
In the notoriously fickle Ardennes region, the sport's figures were surprised as they arrived at the fabled circuit to find a bright and dry paddock.
"Good news — really warm and sunny at Spa," said Virgin Racing on its official Twitter channel.
Shortly afterwards, Mercedes GP reported: "Oh wait … it is now raining."
The Telegraph's Tom Cary was more eloquent as he described how the "blue skies and sunshine have given way to thick white cloud and fine mist-like rain".
The official forecast is for a probably wet Friday ahead of potential rain for qualifying, with Sunday likely to be better.
But championship leader Sebastian Vettel said the most predictable forecast is for a weekend "full of surprises".
"Spa can be raining one minute and then the sun can be shining the next."
Agreed Force India's Adrian Sutil: "We should probably expect some more rain showers this weekend."