Explanation

Raag Malhar (Miyan ki Malhar and its variants) is the Hindustani classical raga traditionally sung as an invitation to rain and is associated with the monsoon. Raag Yaman is an evening raga, Raag Bahar celebrates spring, and Raag Bhairavi is a morning/devotional raga. Hence the rain-invoking raga is Raag Malhar.