1. During the pre-monsoon season, when the summer solstice (June 21st) is approaching, the temperatures generally increase, as the sun shines vertically on 23/4 North, Tropic of Cancer.
2. They are generally much higher in the southern portion closer to the equator. This is the northern portion of the Indian Ocean.
3. Therefore, temperatures are high in pre-monsoon season in equatorial region in northern Indian Ocean.