In Oahu the whales start coming around the end of October. January and February seems to be the height of the whale season. I see them almost every day in my job as both a scuba diving instructor and on the submarine. Unfortunately I only see them on the surface, never underwater. The whales are so prevalent here that the whale watching tour has a 100% guarantee of seeing whales. If there are no whale sightings on the tour then if one takes another tour during the season then it is for free! Usually there are whales as soon as the boat leaves the harbor. One almost always sees both the Mother and the baby. If a single whale is spotted then it is almost always a male.