Canadian GP: More rain possible for second practice
The asphalt was pretty wet when the lights turned green at 10am, thus ensuring that the busiest period of the initial 90 minute session was when it was at its driest at the end.
It is expected to remain very overcast for the afternoon session, with a 40 per cent chance of more – and possibly quite heavy – rain.
The temperatures at 2pm, the start-time for afternoon practice, should also climb from the morning's mild teens to 25-26C.
Qualifying-day Saturday, meanwhile, is expected to stay cloudy, but the probability of rain should subside significantly overnight.
As a dry line became clearer late on Friday morning, Ferrari's Felipe Massa ultimately set the fastest time from the BMW-Sauber of Robert Kubica, while championship leader Lewis Hamilton did the least number of laps of any driver, slotting into the sixth quickest spot.
Several drivers ran over grass verges or half-spun, but there were no significant incidents, such as contact with the barriers.