You can find the months specific data from worldometer.com or the official sites. I also find the COVID-19 Cases from some of the news sites. Hope it helps.
If you are looking for a dataset, you may try this COVID-19 Data Github page (https://github.com/owid/covid-19-data/tree/master/public/data) by Our World in Data which is updated daily. This includes data on confirmed cases, deaths, and testing, as well as other variables of potential interest