Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 11 · Rain, Kurma Chakra, Utpata
वृष्टिः कूर्मचक्रम् उत्पाताश्च
प्रावृषींदुः सितात्सप्तराशिगः शुभवीक्षितः ।मंदात्रिकोणसप्तस्थो यदि वा वृद्धिकृद्भवेत् ॥ ७२३ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 723.
In the rains, the Moon may be in the 7th sign from Venus, seen by good planets. Or it may be in a trikona (luck house) or the 7th from Saturn. Then it brings more rain.
Simple meaning: In the rains, the Moon in these places can bring more rain.
सद्यो वृष्टिकरः शुक्रो यदा बुधसमीपगः ।
Venus close to Mercury brings quick rain. The Sun between them can stop the rain.
मघादिपंचधिष्ण्यस्थः पूर्वे स्वातित्रये परे ।
Venus in these stars brings heavy rain. The other way round, it brings none.
पुरतः पृष्ठतो भानोर्ग्रहा यदि समीपगाः ।
Planets close to the Sun, in front or behind, bring rain. Backward ones do not.