SB 5.21.5
yada vrscikadisu pañcasu vartate tadaho-ratrani viparyayani bhavanti.
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When the sun passes through the five signs beginning with Vrscika [Scorpio], the duration of the days decreases [until Capricorn], and then gradually it increases month after month, until day and night become equal [in Aries].