If you are a day trader, every day is a trading day. Day trading is quite hard to manage if we are not a full-time trader, it is very important to always on the track of our trades otherwise we miss something. Every fluctuation is very important in day trading and we need to take it seriously..or lost everything you have..
As you said, numbers and events, value changes are very important for trading day, and almost all of these factors belong to random time frames, and so, we don't have a fixed time frame for trading the day, opportunities depend on our perspective and analysis, combined with the information we receive. Many time for these numbers, we will make more profit, less time for it, trading day will turn into disaster for us, so the rule is not to set a fixed time for trading day, fixed will create limited space, affecting the process of analyzing and seeking income