Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Portents, Comets
ग्रहचारः केतवश्च
स्वातित्रये पश्चिमायां तस्यां शुक्रस्तथाविधः ।विपरीते त्वनावृष्टिर्वृष्टिवृद्बुधसंयुतः ॥ ६९ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 69.
In the three stars from Svati, Venus seen in the west is the same. In the opposite case there is no rain. Joined with Mercury, Venus adds rain.
Simple meaning: Venus in the west in the Svati group also brings rain. The opposite brings drought; Mercury adds rain.
कृष्णाष्टम्यां चतुर्दश्याममायां च यदा सितः ।
Venus rising or setting on those days tends to bring heavy rain.
मिथः सप्तमराशिस्थौ पश्चात्प्राग्वीथिसंस्थितौ ।
Jupiter and Venus opposite each other, one west and one east, can bring drought, famine and war.
कुजज्ञजीवरविजाः शुक्रस्याग्रेसरा यदि ।
Mars, Mercury, Jupiter and Saturn moving ahead of Venus can bring war, storms, famine and drought.