Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 11 · Rain, Kurma Chakra, Utpata
वृष्टिः कूर्मचक्रम् उत्पाताश्च
पुरतः पृष्ठतो भानोर्ग्रहा यदि समीपगाः ।तदा वृष्टिं प्रकुर्वन्ति न ते चेत्प्रतिलोमगाः ॥ ७२६ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 726.
Planets may stand near the Sun, in front of it or behind it. Then they bring rain. They do not, if they are moving backward.
Simple meaning: Planets close to the Sun, in front or behind, bring rain. Backward ones do not.
वामभागास्थितः शुक्रो वृष्टिकृच्चेत्तु याम्यगः ।
Venus on the left side, in the south, brings rain. So do its rising, setting and the Sun entering Ardra.
संध्ययोः सस्यवृद्धिः स्यात्सर्वसंपन्नृणान्निशि ।
Rain at twilight helps crops and at night brings wealth. Little rain makes grain costly.
आर्द्रोदयेग्रभिन्ना चेद्भवेदिति न संशयः ।
The Moon, Jupiter, Mercury or Venus in a corner house ends the plague on crops.