extraire le mois d'une date en vba avec Application.WorksheetFunction

Sub Mois()
Range("AE3:AE" & Rows.Count) = "" 'RAZ
With Range("AE3:AE" & Range("A" & Rows.Count).End(xlUp).Row)
  If .Row < 3 Then Exit Sub
  .Formula = "=MONTH(A3)"
  .Value = .Value
End With
End Sub

Option Explicit
Sub Mois()
    Dim c As Range
    Columns(2) = ""
    For Each c In Columns(1).SpecialCells(xlCellTypeConstants)
        If IsDate(c) Then c(1, 2) = Month(c)
    Next
End Sub

Option Explicit
Sub Mois_en_colonne_ae()
    Dim c As Range
    Columns(2) = ""
    For Each c In Columns(1).SpecialCells(xlCellTypeConstants)
        If IsDate(c) Then c(1, 31) = Month(c)
    Next
End Sub