Bhagavad Gita 8.25

धूमो रात्रिस्तथा कृष्णः षण्मासा दक्षिणायनम्।तत्र चान्द्रमसं ज्योतिर्योगी प्राप्य निवर्तते॥

dhūmo rātristathā kṛṣṇaḥ ṣaṇmāsā dakṣiṇāyanam |tatra cāndramasaṃ jyotiryogī prāpya nivartate ||

Attaining the lunar light through smoke, night time, the dark fortnight, and the six months of the southern path of the sun (the southern solstice), the yogi returns.

But if he departs in gloom, at night, during the fortnight of the waning moon and in the six months before the winter solstice, then he reaches only lunar light and he will be reborn.

Our plain-language meaning of this verse is waiting for scholar review.