Android Question Knowing if DST is active for a prior or future date

Sub IsDaylightInEffect As Boolean
    Dim currentTimezone As Double = DateTime.TimeZoneOffset
    Dim t As Long = DateTime.Now
    For i = 0 To 11 Step 2
        If DateTime.GetTimeZoneOffsetAt(t) < currentTimezone Then Return True
        t = t + i * DateTime.TicksPerDay * 30
    Next
    Return False
End Sub

Sub Process_Globals
   Private MinTimeZone As Double
End Sub

Sub Activity_Create(FirstTime As Boolean)
   If FirstTime Then
       FindMinTimeZone
   End If
   Log(IsDST(DateTime.Now))
   Log(IsDST(DateTime.DateParse("08/01/2000")))
End Sub

Private Sub FindMinTimeZone
   Dim t As Long = DateTime.Now
   MinTimeZone = DateTime.GetTimeZoneOffsetAt(t)
   For i = 1 To 400
       Dim m As Double = DateTime.GetTimeZoneOffsetAt(t)
       If m <> MinTimeZone Then
           MinTimeZone = Min(m, MinTimeZone)
           Exit
       End If
       t = t + DateTime.TicksPerDay
   Next
End Sub

Public Sub IsDST(t As Long) As Boolean
   Return DateTime.GetTimeZoneOffsetAt(t) > MinTimeZone
End Sub

IsDST( t + DateTime.TicksPerHour*12)