The exact timing of the dolphin mating season varies depending on the species and their geographical location. Generally, for most species of dolphins, the mating season occurs during the warmer months of the year. In some regions, this can be in spring or summer when water temperatures are higher and food is more plentiful. However, for certain species in different areas, the mating season may occur at different times. Additionally, factors such as water temperature, prey availability, and social interactions can also influence the timing of the mating season. Therefore, it is difficult to give a specific date or time frame for the dolphin mating season without specifying the species and their habitat.