MONTH DAX Function
The MONTH function returns the month as a number from 1 (January) to 12 (December).
DAX Syntax MONTH(date)
The parameter data is a date in datetime format, or a text representation of a date.
Example: Create a Calculated Column. The following expression returns the month from the date in the Date of Birth column of the Sheet1 table.
DAX
Month Column = MONTH('Sheet1'[Date of Birth])