Bonsoir,
Je ne suis pas sûr d'avoir bien compris, mais peut-être ainsi :
Private Sub Workbook_Open()
Dim ws As Worksheet, d, k%, h%, n%
d = DateSerial(Year(Date), Month(Date) + 3, 1)
Set ws = Worksheets("Resume")
Do
h = h + 1: If ws.Cells(3, h) = d Then d = 0: Exit Do
Loop While ws.Cells(3, h) <> ""
If d > 0 Then
With Worksheets("Data")
Do
k = k + 1
Loop Until .Cells(3, k) = d
n = .Cells(.Rows.Count, k).End(xlUp).Row - 2
ws.Cells(3, h).Resize(n).Value = .Cells(3, k).Resize(n).Value
End With
End If
End Sub
Cordialement.