> The first question is: which specific time? This time will differ based on the timezone and geography.
That's not what it's about. The specific time is irrelevant - that's just an arbitrary number. The reasoning in the blog posts you link to is just based around making comparisons to another arbitrary number (7 AM).
Rather, the point is shape of the curve. DST makes the sunrise time approximate a constant line.
In other words, if you plotted the time difference between sunrise and "x o'clock" (for any x) for every day across the year, DST reduces the standard deviation of those values.
The argument is that circadian rhythm causes humans to naturally wake up near sunrise. Most people also wake up at some fixed time in order to start their workday (because businesses generally have fixed hours, and people wake up just before going to work). DST makes it so that the difference between this fixed time and 'sunrise' can be minimized over the year. Without DST, you will not be able to have a fixed wake-up time and also minimize the difference between that time and sunrise.
That's not what it's about. The specific time is irrelevant - that's just an arbitrary number. The reasoning in the blog posts you link to is just based around making comparisons to another arbitrary number (7 AM).
Rather, the point is shape of the curve. DST makes the sunrise time approximate a constant line.
In other words, if you plotted the time difference between sunrise and "x o'clock" (for any x) for every day across the year, DST reduces the standard deviation of those values.
The argument is that circadian rhythm causes humans to naturally wake up near sunrise. Most people also wake up at some fixed time in order to start their workday (because businesses generally have fixed hours, and people wake up just before going to work). DST makes it so that the difference between this fixed time and 'sunrise' can be minimized over the year. Without DST, you will not be able to have a fixed wake-up time and also minimize the difference between that time and sunrise.