The six seasons within each day

Each day runs through the six seasons as the year does: forenoon is spring, midday summer, afternoon or evening prāvṛṭ, the first part of the night the rains, midnight autumn and the pre-dawn hours (about 4 a.m.) hemanta. A footnote says this is given so that one can know at what time of day each dosha accumulates or is aggravated.