You will see a link in the email, that will take you to this page ==> https://news.stake.com/how-do-monthly-bonuses-work/ ..explaining a bit more about the Monthly and how it works.
I want to highlight this :
7. When will my monthly bonus arrive?
This is something we like to keep a secret.
I think for obvious reasons, Stake cannot have fixed dates for the Monthly... because a lot of work has to be done to prepare that and if they are late.. people will spam the Support and the mods and Eddie.
Of course streaming the games and live betting while watching are all great stuff everyone can enjoy, those are still very cool stuff, and I remember there were (haven't checked in a while sorry) donations to charity as well, all of which is awesome and the reason I still do play here, but it was never about "what will I get back for gambling here" because only whales get proper while I get nearly nothing, so it is about purely gambling and nothing more.
Many people cares about reload although it is just small amount as it gives them extra balance to play.
Also bear in mind that not all players get reload, those who are in higher rank get the bonus in a direct balance with nice amount based on their rank and wagering stats.
This is why many players are waiting for the monthly bonus every month especially when it is getting closed to the middle of the month.