Revenue low near end of the month


I have 6 apps which earn me averagely $8 to $10 per day.
But i realized that the revenue drops to $3 to $4 near end of the month with the same impression.
Is it got to do with the advertiser campaign ending during this period.
Anyone can share your experience?
Thank you.

It could be that. eCPMs generally fluctuate week by week and month by month. Admob has gone up and down a lot for my this year.
If you haven’t made changes to these apps then I would just take it as the natural fluctuation.

May be end of month, most campaigns end and start next month?