which day is the last i could upload offline data for CLV in a month?

We are using offline data loading for predictive CLV, the scenario we want to achieve is the following:
We can perform the offline load with the complete data from JAN to FEB 15. In this example, we will have an analysis in MARCH that considers the data from JANUARY, since the CLV is only updated at the end of FEB. Therefore, to avoid this gap, the ideal would be to perform the OFFLINE load on the last business day of the month, with the data from the month. Therefore, we need to know:

What is the last day of the month that we can perform the offline load, so that the most recent data possible is considered in the analysis?