वर्षादि दक्षिणायनम् ॥ कZ_०२.२०.६२ ॥
varṣa-ādi dakṣiṇāyanam
Dakṣiṇāyaṇa begins with Varṣā (the rainy season).
Because rains constrain movement, affect agriculture and revenue timing, and require distinct administrative scheduling (storage, relief, road maintenance).