Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 5 · Portents, Comets
ग्रहचारः केतवश्च
वैशाखे श्रावणे पौषे आषाढेऽभ्युदितो बुधः ।जगतां पापफलदस्त्वितरेषु शुभप्रदः ॥ ५१ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 51.
Mercury risen in Vaishakha, Shravana, Pausha or Ashadha brings bad results to the world. In the other months it brings good.
Simple meaning: Mercury rising in some months brings bad results to the world. In other months it is good.
इषोर्जमासयोः शस्त्रदुर्भिक्षाग्निभयप्रदः ।
Mercury rising in Ashvina or Kartika brings weapon, famine and fire fear. A silver-white Mercury is best.
कार्तिको मार्गशीर्षश्च नृणां दुष्टफलप्रदः ।
Kartika and Margashirsha are bad for people. Pausha and Magha are good. Phalguna and Chaitra are middling.
माधवः शुभदो ज्येष्ठो नृणां मध्यफलप्रदः ।
Vaishakha, Shravana and Bhadrapada are good. Jyeshtha and Ashadha are middling.