Rally Deutschland leader Sebastien Loeb admitted there could be an element of lottery about Friday afternoon's three stages - with the weather ready to turn wet at any point.
Rain was forecast for Friday morning, but the overnight downpours had all dried up by the time the cars headed into the opening test.
"It was damp in some places in the first stage," said Loeb, "I expected it to be much more damp - I was cautious in places. This afternoon is interesting - what will happen?
"We have seen in the past it can be very difficult if you get the big rain when you are waiting to start the stage; anything can happen."
Both Ford and Citroen are reporting an increased chance of rain through the afternoon and the factory Fiesta RS WRC and Citroen DS3 WRCs both went out with two soft compound spare tyres in the boot.
Whether it rains or not, progress through the afternoon is likely to be more sedate after the whole field has passed through.
"This afternoon I think it will be more like driving off-road," said Ott Tanak. "We were 10th on the road or something like that this morning and it was really tough in some places, there was so much mud more than I expected."
Friday's Rally Deutschland is the first all-asphalt round of the 2012 World Rally Championship. The leading crews have a choice of hard and soft Michelins to run on for the stages north of the event's Trier base.