After Lewis Hamilton pulled out of 2017 Pirelli tyre testing, Pascal Wehrlein stepped up and completed 31 laps on the Circuit de Catalunya on a damp surface.
Rain hampered both days of testing, with Nico Rosberg suffering the day before as he only managed to rack up 60 laps.
Pirelli motorsport director Paul Hembery confirmed the weather difficulties and added to the speculation that they could move 2017 testing to a warmer climate so they can accurately gather data on the tyres.
"Obviously the weather hindered progress to some extent both today and yesterday, as is not entirely unexpected at this time of year in Europe," he said in statement.
"The same can apply to the early part of next year, which is why we are in favour of some guaranteed warm weather testing in 2017, before the season gets underway."
The next Pirelli test for the season will be conducted by Red Bull in Abu Dhabi between the 14th and 16th of October.