The first winter test was scheduled to take place between Monday and Thursday, but snow is forecast in Barcelona on Wednesday.
Not just that, low temperatures are already affecting the teams’ ability to get sufficient heat into the tyres.
“The weather is the biggest problem,” Ferrari’s Kimi Raikkonen said after Monday’s running.
“It’s about 8 degrees and that’s just too cold.”
Renault’s Nico Hulkenberg agrees: “It was a bit scary at first because it was like driving in the wet.”
As for the snow forecast for Wednesday, Fernando Alonso said: “If it’s like that, we will not drive much and that’s a shame for the fans.”
Due to the forecast, some teams are proposing to extend the test until Friday, potentially cancelling Wednesday’s running altogether.
“I’ve heard that,” Renault driver Carlos Sainz told El Mundo Deportivo newspaper.
“Personally I’d like it because Friday will be a normal day in Barcelona — cool but sunny. If it happens, it’s great,” he said.