In the 747, the cargo hold temp control can be turned off. In that case the temp can get to -20 or so at altitude, and above outside temp on the ground. A small amount of heated air flows via the Aft Cargo Heat, but that is along the floor of the Bulk area aft of the cargo floor.
With temp control ON, the range is 4-29C. However, depending on the starting temperature on the ground, it may take an hour or more to stabilize.