If I not miss something, you need to get local time on remote machine and it time zone offset, right?
Here I see self-answer based on WMI Win32_TimeZone Bias property. But according to this MSDN example: "Converting Local Time to UTC Time", quote:
Use Win32_ComputerSystem CurrentTimeZone property, because it
automatically adjusts the Time Zone bias for daylight saving time
Win32_TimeZone Bias property does not.
So, next example function get current date time, and I'll leave to you to modify it for concrete date time measuring.
' "." mean local computer
WScript.Echo FormatDateTime(UTCDate("."), 0)
Function UTCDate(strComputer)
Dim objWMIService, ColDate, ColCS
On Error Resume Next
Set objWMIService = _
GetObject("winmgmts:{impersonationLevel=impersonate}!\\" _
& strComputer & "\root\cimv2")
Set ColDate = objWMIService.ExecQuery("Select * From Win32_LocalTime")
UTCDate = DateSerial(100, 1, 1)
For Each objDate In ColDate
UTCDate = DateAdd("yyyy", ObjDate.Year - 100, UTCDate)
UTCDate = DateAdd("m", ObjDate.Month - 1, UTCDate)
UTCDate = DateAdd("d", ObjDate.Day - 1, UTCDate)
UTCDate = DateAdd("h", ObjDate.Hour, UTCDate)
UTCDate = DateAdd("n", ObjDate.Minute, UTCDate)
UTCDate = DateAdd("s", ObjDate.Second, UTCDate)
Next
' http://msdn.microsoft.com/en-us/library/windows/desktop/ms696015(v=vs.85).aspx
Set ColCS = objWMIService.ExecQuery("Select * From Win32_ComputerSystem")
Dim TimeZoneOffset, LocalTimeZone
For Each LocalTimeZone In ColCS
TimeZoneOffset = LocalTimeZone.CurrentTimeZone
Next
If TimeZoneOffset < 0 Then
TimeZoneOffset = Abs(TimeZoneOffset)
Else
TimeZoneOffset = -Abs(TimeZoneOffset)
End If
UTCDate = DateAdd("n", TimeZoneOffset, UTCDate)
If Err Then UTCDate = vbNull
Set objWMIService = Nothing
End Function
[EDIT] Well, looks like should not trust on MSDN then (or maybe this work only for current time). However, I see it's not the answer you looking for. If you not find better idea, you may automate this online calculator.
P.S. Ok, strike out above code and lets try another "iteration".
Just to note that I made a code compatible with my time zone (Bulgaria), where PDT start at last Sunday of March and end at last Sunday of October. This allow me to set easy my PDT range. Shortly, the idea is to make algorithm applicable to your region. The rest is clearly, I hope.
With New DateDrill
Debug.WriteLine .UTCDate("2008-6-28")
Debug.WriteLine .UTCDate("2014-1-21")
End With
Class DateDrill
Public Function UTCDate(ByVal dtDate)
If Not IsDate(dtDate) Then Err.Raise 5
dtDate = CDate(dtDate)
Dim ZoneBias: ZoneBias = TimeZoneBias()
If IsPDT(Now) <> IsPDT(dtDate) Then
ZoneBias = ZoneBias - 60
End If
UTCDate = DateAdd("n", ZoneBias, dtDate)
End Function
Private Function IsPDT(ByVal dtDate)
If Not IsDate(dtDate) Then Err.Raise 5
dtDate = CDate(dtDate)
Dim pdtLow, pdtUpr, nDaysBack
pdtLow = DateSerial(Year(dtDate), 3, 31)
pdtUpr = DateSerial(Year(dtDate), 10, 31)
pdtLow = DateAdd("h", 2, pdtLow)
pdtUpr = DateAdd("h", 2, pdtUpr)
nDaysBack = Weekday(pdtLow) - 1
If nDaysBack <> 0 Then
pdtLow = DateAdd("d", -nDaysBack, pdtLow)
End If
nDaysBack = Weekday(pdtUpr) - 1
If nDaysBack <> 0 Then
pdtUpr = DateAdd("d", -nDaysBack, pdtUpr)
End If
IsPDT = (dtDate >= pdtLow And dtDate <= pdtUpr)
End Function
Private Function TimeZoneBias()
Dim LTZone
With GetObject("winmgmts:" & _
"{impersonationLevel=impersonate}!\\.\root\cimv2")
For Each LTZone In .ExecQuery(_
"Select * From Win32_ComputerSystem")
TimeZoneBias = LTZone.CurrentTimeZone
Next
End With
TimeZoneBias = TimeZoneBias * -1
End Function
End Class
