Bonjour,
Une autre proposition VBA.
Sub ColorCells()
Dim rng As Range, Cell As Range
With ActiveSheet
Set rng = .Cells(1).CurrentRegion
For Each Cell In rng
If IsDate(Cell) Then
If Hour(Cell) = 0 Or Hour(Cell) = 12 Then Cell.Interior.Color = 65535
End If
Next Cell
End With
End Sub