Garudapurana 1.50.11

1.50.11

gavāṃ hi rajasā proktaṃ vāyavyaṃ snānamuttamam /
yattu sātapavarṣeṇa snānaṃ taddivyamucyate //

The vāyavya bath is declared to be the best, performed with dust [raised by] cows; / And the bath that is taken in rain accompanied by sunshine is called divya;