Examples: IsDST property (NotesDateTime - LotusScript®)
This script creates a NotesDateTime object, sets it to today's date and time, and checks whether daylight-saving time is currently in effect or not.
Dim dateTime As New NotesDateTime( "" )
Call dateTime.SetNow
If dateTime.IsDST Then
Messagebox( "Enjoy the long days." )
Else
Messagebox( "Endure the darkness." )
End If