SB 5.21.4
यदा मेषतुलयोर्वर्तते तदाहोरात्राणि समानानि भवन्ति यदा वृषभादिषु पञ्चसु च राशिषु चरति तदाहान्येव वर्धन्ते ह्रसति च मासि मास्येकैका घटिका रात्रिषु ॥ ४ ॥
SYNONYMS

yadā—when; meṣa-tulayoḥ—in Meṣa (Aries) and Tulā (Libra); vartate—the sun exists; tadā—at that time; ahaḥ-rātrāṇi—the days and nights; samānāni—equal in duration; bhavanti—are; yadā—when; vṛṣabha-ādiṣu—headed by Vṛṣabha (Taurus) and Mithuna (Gemini); pañcasu—in the five; ca—also; rāśiṣu—signs; carati—moves; tadā—at that time; ahāni—the days; eva—certainly; vardhante—increase; hrasati—is diminished; ca—and; māsi māsi—in every month; eka-ekā—one; ghaṭikā—half hour; rātriṣu—in the nights.

TRANSLATION

When the sun passes through Meṣa [Aries] and Tulā [Libra], the durations of day and night are equal. When it passes through the five signs headed by Vṛṣabha [Taurus], the duration of the days increases [until Cancer], and then it gradually decreases by half an hour each month, until day and night again become equal [in Libra].