Not necessarily. As I said, the engine needs to get up to operating temperatures. Depending on how cold it is outside the engine may not get up to the proper temperature as the outside air keeps the engine cooler than it should be while running. This could be bad because if the engine isn't hot enough during break-in the parts will not wear in properly, then when the plane is flown the engine can wear abnormally because it was never broken in properly.

Ken