I find it curious that the volume of users are similar for day of the month regardless of year. For instance the first of the month is not always the same day of the week.
Eyeballing the data, there doesn't seem to be a strong weekday effect. Not sure if this is real data (human activity data usually show weekday effects).
If there was a very pronounced weekday effect, a quick hack is to use a 364-day instead of full-year offset for comparison.
