Gettting value from ENUM using its position

Refer- Enum.GetName Method[^].
You can do like below to get the Enum constant name from value.

Enum.GetName(typeof(monthToVal), 2);

You did not check out the documentation[^], did you?

Why not do this all the correct way - with a data array?

Create a structure for all your desired data, such as:

struct YearParts { 
  int monNum;  // Month Number 1-12
  int monSize; // Days In Month (don't forget to test for leap-year!)
  string monShort; // Three-char month name
  string monLong;  // Full Month Name
  bool leapYr;
};

Assign them to an array - you may even make the array length 13, and make your Jan as index 1.

You could, if you wish, still use your enum as an alternative way to select an index.

They could be made public, put in an include file, and be available everywhere as your personal standard.