Brihat Samhita
प्रायो ग्रहाणां उदयास्तकाले समागमे मण्डलसंक्रमे च । पक्षक्षये तीक्ष्णकरायनान्ते वृष्टिर्गते अर्के नियमेन चार्द्राम् ॥ २८-२० ॥
Generally, there will be rain at the periods of heliacal rising and setting of the planets, planetary conjunctions, of new and full moons, when the Sun is at the end of his Ayana (course to the north or south) and when the Sun is in the asterism of Ārdrā.
english translation
prAyo grahANAM udayAstakAle samAgame maNDalasaMkrame ca । pakSakSaye tIkSNakarAyanAnte vRSTirgate arke niyamena cArdrAm ॥ 28-20 ॥
hk transliteration by Sanscript