I'd suggest that technically it starts at midnight, but that your definition falls in step with another response here that suggests It truly is according to how we truly feel over it. BVernon "Day and night time" is more ambiguous whether the "time" is intended being tightly bound to "night" https://knoxsg197.blogitright.com/38121364/facts-about-night-gangnam-퍼펙트가라오케-karaoke-guide-revealed