Matsya Purana — Glory of Tīrtha-Śrāddha: Best Times
मध्याह्ने सर्वदा यस्मान् मन्दीभवति भास्करः तस्मादनन्तफलदस् तदारम्भो विशिष्यते //
madhyāhne sarvadā yasmān mandībhavati bhāskaraḥ tasmādanantaphaladas tadārambho viśiṣyate //
Because at midday the Sun’s intensity becomes tempered, an undertaking begun at that time is regarded as especially excellent and is said to yield boundless results.
This verse does not describe pralaya; it gives a practical rule of auspicious timing, praising midday as a superior time to begin an undertaking.
It advises choosing proper timing for initiating dharmic acts—such as vows, donations, rites, or public works—so that a king or householder begins actions under a recommended muhūrta believed to enhance success and merit.
For rituals and even Vastu-related commencements (foundation-laying, consecration preliminaries), the verse highlights madhyāhna as a particularly auspicious start-time, said to confer abundant results.